Radiofrequency ablation of tissue within a vertebral body

ABSTRACT

Methods and systems for modulating intraosseous nerves (e.g., nerves within bone) are provided. For example, the methods and systems described herein may be used to modulate (e.g., denervate, ablate) basivertebral nerves within vertebrae. The modulation of the basivertebral nerves may facilitate treatment of chronic back pain. The modulation may be performed by a neuromodulation device (e.g., an energy delivery device).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/153,242, filed Oct. 5, 2018, which is a continuation of U.S.application Ser. No. 15/344,284, filed Nov. 4, 2016, now U.S. Pat. No.10,111,704, which is a continuation of U.S. application Ser. No.14/673,172, filed Mar. 30, 2015, now U.S. Pat. No. 9,486,279, which is acontinuation of U.S. application Ser. No. 13/923,798, filed Jun. 21,2013, now U.S. Pat. No. 8,992,523, which is a continuation of U.S.application Ser. No. 13/615,300, filed Sep. 13, 2012, now abandoned,which is a continuation of U.S. application Ser. No. 13/612,541, filedon Sep. 12, 2012, now U.S. Pat. No. 8,361,067, the content of each ofwhich is incorporated herein by reference in its entirety. The contentof each of U.S. application Ser. No. 12/683,555, filed on Jan. 7, 2010,now U.S. Pat. No. 8,613,744; U.S. application Ser. No. 12/566,895, filedon Sep. 25, 2009, now U.S. Pat. No. 8,419,730; and U.S. ProvisionalApplication No. 61/100,553 filed on Sep. 26, 2008; is also incorporatedherein by reference in its entirety.

FIELD

Various embodiments of the invention pertain generally to generatingpassageways through tissue and to treatment or monitoring ofintraosseous nerves, and more particularly to creating curved paths inbone and to treatment of basivertebral nerves within vertebral bodies ofthe spine.

BACKGROUND

Back pain is a very common health problem worldwide and is a major causefor work-related disability benefits and compensation. Back pain mayarise from strained muscles, ligaments, or tendons in the back and/orstructural problems with bones or spinal discs. The back pain may beacute or chronic. Treatments for chronic back pain vary widely andinclude physical therapy and exercise, chiropractic treatments, rest,pharmacological therapy such as pain relievers or anti-inflammatorymedications, and surgical intervention such as vertebral fusion,discectomy or disc repair. Existing treatments can be costly, addictive,temporary, ineffective, and/or can increase the pain or require longrecovery times.

SUMMARY

The technique of accessing the vertebral body through minimally invasivemeans has been developed through the surgical techniques used invertebroplasty and kyphoplasty. Although accessing the vertebralsegments of the spine through the pedicle and into the lateral/anteriorsection of the body of the vertebra is a primary method of placing atreatment device or neuromodulation device (e.g. a bone cement deliverydevice, a chemical agent delivery device, and/or an RF probe) into thevertebra, it can be difficult to place a probe in the posterior midlinesection of the vertebra. Furthermore, accessing the posterior midlinesection of the S1 segment of the spine can be difficult with a straightlinear access route. In several embodiments, a probe or other treatmentdevice (e.g., neuromodulation device) advantageously is capable ofnavigating to the posterior section of the S1 vertebral segment, as wellas to the same target area within a lumbar vertebral segment. Inaddition, in accordance with several embodiments, vertebral segments inthe cervical and thoracic regions of the spine may also be targeted.

In order to accurately and predictably place a treatment device (e.g.,neuromodulation device such as an energy or fluid delivery catheter orprobe) in the posterior section of a lumbar vertebral body, a sacralvertebral body or other level vertebral body, the device or probe maynavigate to the target area through varying densities of bone in someembodiments. However, due to the varying densities of bone, it can bedifficult to navigate a probe in bone and ensure its positioning will bein the posterior (e.g., posterior to the midline) or posterior midlinesection of the vertebral body. Accordingly, several embodiments of theinvention are directed to a system and method for generating a path inbone that predictably follows a predetermined curved path. Theneuromodulation devices described herein can be configured to performany of the method steps recited herein.

Several embodiments of the invention are directed to systems and methodsto deploy and navigate a flexible treatment instrument, such as aneuromodulation device (e.g., a radiofrequency (RF) bipolar probe, amicrowave energy delivery device, a fluid or agent delivery device)within bone. Although the systems and methods described herein areprimarily directed to navigating through the bone of a vertebral memberof the spine, and particularly to treat the basivertebral nerve (BVN) ofa vertebral member, the treatment may be applied to any tissue segmentof the body.

Several embodiments of this invention advantageously provide the abilityto navigate a curve or angle within varying densities of cancellous boneand create a straight channel at the end of the navigated curve orangle.

In accordance with several embodiments, a method of therapeuticallytreating a vertebral body having an outer cortical bone region and aninner cancellous bone region, and a BVN having a trunk extending fromthe outer cortical bone region of the vertebral body into the innercancellous region of the vertebral body and a plurality of branchesextending from the trunk to define a BVN junction or terminus, comprisesthe steps of: a) inserting one or more energy devices into the vertebralbody, and b) exclusively depositing energy within the inner cancellousbone region of the vertebral body between, but exclusive of, the BVNjunction and the outer cortical bone region, to denervate the BVN. Insome embodiments, the method comprises depositing, or delivering,energy, fluid, or other substance at or proximate (e.g., posterior to)the BVN junction, or terminus. In some embodiments, a delivery probe fordelivering a non-energy therapeutic is provided instead of, or inaddition to, the energy device.

In some embodiments, a tube-within-tube system comprises a deployablecurved tube (e.g. comprised of Nitinol or other flexible, elastic, orshape memory material) that deploys from a straight cannula. The tubecan be pre-curved to create an angular range of approximately 0° toapproximately 180° (e.g., from approximately 45° to approximately 110°,from approximately 15° to approximately 145°, from approximately 30° toapproximately 120°, from approximately 60° to approximately 90°, fromapproximately 10° to approximately 45°, overlapping ranges thereof, orany angle within the recited ranges), when fully deployed from thestraight cannula. The design of the curve can be such that a flexibleelement (e.g., probe carrying a treatment device) can navigate throughthe angular range of deployment of the curved tube. The curved tube canallow the flexible element to navigate through a curve within cancellousbone tissue without veering off towards an unintended direction.

Cancellous bone density varies from person to person. Therefore,creating a curved channel within varying density cancellous bone may notpredictably or accurately support and contain a treatment device as ittries to navigate the curved channel. With some embodiments, theflexible element is deployed into the bone through the curved tube,which supports the flexible element as it traverses through the curve,thereby preventing the flexible element from channeling its own path.When the flexible element (e.g., energy or agent delivery probe) departsfrom the tube, it can do so in a linear direction towards the targetzone or location. In accordance with several embodiments, this designallows the user to predictably and accurately deploy the flexibleelement (e.g., treatment device) towards the target zone or locationregardless of the density of the cancellous bone.

One embodiment of the invention comprises a system for channeling a pathinto bone. The system may comprise a trocar having a central channel andopening at its distal tip, and a cannula sized to be received in saidcentral channel and to be delivered to the distal opening. The cannulamay comprise a deflectable or deformable tip with a preformed curve suchthat the tip straightens while being delivered through the trocar andregains its preformed curve upon exiting and extending past the distalopening of the trocar to generate a curved path in the bonecorresponding to the preformed curve of the deflectable or deformabletip. At least the distal tip or distal section of the cannula maycomprise a resiliently deformable material (such as Nitinol or othershape memory material). The cannula may comprise a central passageway orlumen having an internal diameter configured to allow a treatment deviceto be delivered through the central passageway to a location beyond thecurved path in the bone.

In one embodiment, the system further includes a straight styletconfigured to be installed in the trocar, wherein the straight styletcomprises a sharp distal tip that is configured to extend beyond thedistal opening of the trocar to pierce the bone as the trocar is beingdelivered to a treatment location within the bone (e.g., within theinner cancellous bone region of a vertebral body).

The system may further include one or more straightening styletsconfigured to be introduced in the cannula, wherein the straighteningstylet comprises a rigid construction configured to straighten thedistal tip of the curved cannula when positioned in the trocar. In someembodiments, the straightening stylet further comprises a sharp distalend to pierce the bone, and the straightening stylet and curved cannulaare installed or inserted in the trocar in place of the straight styletas the trocar is delivered into the bone.

In some embodiments, the system further comprises a curved stylet havingan outer radius sized to fit within the central passageway of the curvedcannula. The curved stylet is configured to be installed or inserted inthe curved cannula while the curved cannula is extended past the distalopening of the trocar, the curved stylet configured to block the distalopening of the curved cannula while being delivered into the bone. Insome embodiments, the curved stylet advantageously has a curved distalend corresponding to the curve of the curved cannula.

In one embodiment, the curved stylet has a sharp distal tip configuredto extend past the curved cannula to pierce the bone as the cannula isdelivered past the distal opening of the trocar. The curved stylet alsomay advantageously comprise an angled distal tip configured to furthersupport and maintain the curved stylet radius as it is delivered pastthe distal opening of the trocar and into bone. The curved stylet andthe curved cannula may have mating proximal ends (e.g., visual indiciaor corresponding physical mating elements) that align the curve of thecurved stylet with the curve of the curved cannula.

In one embodiment, the system further includes a straight channelingstylet configured to be installed in the curved cannula after removingthe curved stylet, wherein the straight channeling stylet is flexiblydeformable to navigate the curved cannula yet retain a straight formupon exiting the curved cannula. The straight channeling stylet may havea length longer than the curved cannula such that it creates a linearpath beyond the distal end of the curved cannula when fully extended.Curved and/or straightening stylets may be used for non-spinalembodiments.

In accordance with several embodiments, a method for channeling a pathinto bone to a treatment location in the body of a patient is provided.The method includes, in one embodiment, inserting a trocar having acentral channel and an opening at its distal tip into a region of boneat or near the treatment location, and delivering a cannula through thecentral channel and to the distal opening. In one embodiment, thecannula comprises a deflectable or deformable tip with a preformed curvesuch that the tip straightens while being delivered through the trocarand regains its preformed curve upon exiting the trocar, and extendingthe cannula past the distal opening of the trocar to generate a curvedpath in the bone corresponding to the preformed curve of the deflectabletip. In some embodiments, a treatment device is delivered through acentral passageway or lumen in the cannula to the treatment locationbeyond the curved path. The treatment device may facilitate or effectenergy delivery, fluid delivery, delivery of an agent, etc.

In one embodiment, inserting a trocar into a region of bone comprisesinserting a stylet into the trocar such that the stylet extends beyondthe distal opening of the trocar, and inserting the stylet and trocarsimultaneously into the region of bone such that the stylet pierces thebone as the trocar is being delivered to a treatment location.

In one embodiment, delivering a cannula through the central channelcomprises inserting a straightening stylet into the central passagewayof the cannula and inserting the straightening stylet and straightenedcannula simultaneously into the trocar. In one embodiment, thestraightening stylet comprises a rigid construction configured tostraighten the curved distal tip of the cannula. In one embodiment, thestraightening stylet further comprises a sharp distal end to pierce thebone. In one embodiment, the straightening stylet and cannula areinstalled simultaneously along with the trocar as the trocar isdelivered into the bone.

In one embodiment, extending the cannula past the distal opening isperformed by inserting a curved stylet into the central passageway ofthe curved cannula such that a distal tip of the curved stylet extendsto at least the distal opening of the curved cannula and simultaneouslyextending the curved cannula and curved stylet from the distal end ofthe trocar such that the curved stylet blocks the distal opening of thecurved cannula while being delivered into the bone.

In some embodiments, the curved stylet has a curved distal endcorresponding to the curve of the curved cannula such that the curvedstylet reinforces the curved shape of the curved cannula as the curvedcannula is extended past the distal opening of the trocar. The curvedstylet may have a sharp distal tip so that when the curved styletextends past the distal opening of the curved cannula the curved styletis configured to pierce the cancellous bone tissue as the curved cannulais delivered past the distal opening of the trocar.

In some embodiments, the curved stylet is then removed from the curvedcannula, and a straight channeling stylet is inserted into the curveddistal end of the cannula. The straight channeling stylet can beflexibly deformable to navigate the curved cannula, yet retain astraight form upon exiting the curved cannula. The straight channelingstylet can advantageously be longer than the curved cannula to create alinear channel beyond the distal tip of the curved cannula.

In some embodiments, the trocar is inserted through a cortical boneregion and into a cancellous bone region of a vertebral body, and thecurved cannula is extended though at least a portion of the cancellousbone region to a location at or near a target treatment location. Atarget treatment location may comprise a BVN within the vertebra, andtreatment may be delivered to the target treatment location to modulate(e.g., denervate, ablate, stimulate, block, disrupt) at least a portionof the BVN (e.g., terminus or junction or a portion of the BVN betweenthe terminus or junction and the posterior wall). In one embodiment, aportion of the BVN is modulated by delivering focused, therapeuticheating (e.g., a thermal dose) to an isolated region of the BVN. Inanother embodiment, a portion of the BVN is modulated by delivering anagent to the treatment region to isolate treatment to that region. Inaccordance with several embodiments of the invention, the treatment isadvantageously focused on a location of the BVN that is upstream of oneor more branches of the BVN.

In accordance with several embodiments, a kit for channeling a path intobone is provided. The kit comprises a trocar having a central channeland opening at its distal tip, and a cannula selected from a set ofcannulas sized to be received in the central channel and delivered tothe distal opening. The cannula has a deflectable or deformable distaltip with a preformed curve such that the tip straightens while beingdelivered through the trocar and regains its preformed curve uponexiting and extending past the distal opening of the trocar to generatea curved path in the bone corresponding to the preformed curve of thedeflectable tip. The cannula comprises a central passageway or lumenhaving an internal diameter configured to allow a treatment device to bedelivered through the central passageway or lumen to a location beyondthe curved path within bone, wherein the set of cannulas comprises oneor more cannulas that have varying preformed curvatures at the distaltip.

In some embodiments, the one or more cannulas have a varying preformedradius at the distal tip. In addition, the one or more cannulas may eachhave distal tips that terminate at varying angles with respect to thecentral channel of the trocar. The length of the distal tips may also bevaried. The angle of the distal tip with respect to the central channelof the trocar may vary from 0 degrees to 180 degrees (e.g., from 10degrees to 60 degrees, from 15 degrees to 45 degrees, from 20 degrees to80 degrees, from 30 degrees to 90 degrees, from 20 degrees to 120degrees, from 15 degrees to 150 degrees, overlapping ranges thereof, orany angle between the recited ranges). The kit may further include astraight stylet configured to be installed in the trocar, the straightstylet comprising a sharp distal tip that is configured to extend beyondthe distal opening of the trocar to pierce the bone as the trocar isbeing delivered to a treatment location within the bone. The kits may beadapted for non-spinal embodiments.

In some embodiments, the kit includes a set of curved stylets having anouter radius sized to fit within the central passageway of the curvedcannula, wherein each curved stylet is configured to be installed in thecurved cannula while the curved cannula is extended past the distalopening of the trocar. The curved stylet may be configured to block thedistal opening of the curved cannula while being delivered into thebone. In one embodiment, each curved stylet has a varying curved distalend corresponding to the curve of a matching curved cannula in the setof curved cannulas. The curved stylet may have a sharp distal tipconfigured to extend past the curved cannula to pierce the bone as thecannula is delivered past the distal opening of the trocar.

In some embodiments, the kit includes a set of straight channelingstylets wherein one of the set of stylets is configured to be installedin the cannula after removing the curved stylet. The straight channelingstylet can be flexibly deformable to navigate the curved cannula yetretain a straight form upon exiting the curve cannula. Each of thestraight channeling stylets can have a varying length longer than thecurved cannula such that the straight channeling stylet creates apredetermined-length linear path beyond the distal end of the curvedcannula when fully extended.

In accordance with several embodiments, a system for channeling a pathinto bone comprising a trocar with a proximal end, a distal end and acentral channel disposed along a central axis of the trocar andextending from the proximal end toward the distal end is provided. Thetrocar, in one embodiment, comprises a radial opening at or near thedistal end of the trocar, the radial opening being in communication withthe central channel. The system further comprises, in one embodiment, acurveable or steerable cannula sized to be received in said centralchannel and delivered from the proximal end toward said radial opening.In several embodiments, the curveable cannula comprises a curveableand/or steerable distal end configured to be extended laterally outwardfrom the radial opening in a curved path extending away from the trocar,and a central passageway having a diameter configured allow a treatmentdevice (e.g., probe, catheter) to be delivered through the centralpassageway to a location beyond the curved path.

In several embodiments, the curveable cannula comprises a proximal endhaving a proximal body. In one embodiment, the proximal end of thetrocar comprises a housing. The housing may comprise a proximal recessconfigured to allow reciprocation (e.g., alternating back-and-forthmotion or other oscillatory motion) of the proximal body of thecurveable cannula. The proximal recess of the housing may be incommunication with the central channel of the trocar. In severalembodiments, a proximal body of the curveable cannula is configured tobe releasably restrained with respect to translation within the trocarhousing. In several embodiments, the system comprises a probe sized tofit within the central channel of the cannula. The probe may comprise aproximal end configured to be releasably restrained with respect totranslation within the proximal body of the curveable cannula. In oneembodiment, the probe comprises mating threads that mate withcorresponding mating threads of a distal recess of the drive nut so asto allow controlled translation of the probe with respect to the drivenut.

In several embodiments, a spine therapy system is provided. In oneembodiment, the system comprises a trocar having a proximal end, adistal end and a central channel. The central channel can be disposedalong a central axis of the trocar and extend from the proximal endtoward the distal end. In one embodiment, the trocar comprises a radialopening at or near the distal end of the trocar, the radial openingbeing in communication with the central channel. In one embodiment, thetrocar is configured to be deployed through a cortical bone region andinto a cancellous bone region of a vertebral body. In one embodiment, acurveable cannula is configured (e.g., sized) to be received in saidcentral channel and delivered from the proximal end toward the radialopening. The curveable cannula may comprise a central passageway and acurveable and/or steerable distal end configured to be extendedlaterally outward from the radial opening in a curved path extendingaway from the trocar. The curved path may be generated through at leasta portion of the cancellous bone region of the vertebral body. In oneembodiment, a treatment device or probe is configured to be deliveredthrough the central passageway to a location beyond the curved path. Thetrocar, curveable cannula, and/or treatment device can have a sharpdistal end or tip configured to penetrate bone tissue. In someembodiments, the distal ends of the trocar, curveable cannula, and/ortreatment device are rounded or blunt. In some embodiments, the distalends of the trocar or curved or curveable cannula have a full radius onthe inside and/or outside diameter to prevent other devices fromcatching when being pulled back into the distal end after beingdelivered out of the distal end.

In accordance with several embodiments, a method for channeling a pathinto bone to a treatment location in the body of a patient is provided.The bone may be within or proximal a vertebral body, or may benon-spinal (e.g., knee or other joints). In one embodiment, the methodcomprises inserting a trocar into a region of bone near the treatmentlocation. In one embodiment, the trocar comprises a proximal end, adistal end, and a central channel disposed between the two ends. In oneembodiment, the method comprises delivering a curveable cannula throughthe central channel and to a radial opening at or near the distal end ofthe curveable cannula. In one embodiment, the method comprises deployingthe curveable cannula laterally outward from the radial opening in acurved path extending away from the trocar. In one embodiment, themethod comprises steering the curveable cannula (e.g., via a pull cordcoupled to the distal tip of the curveable cannula or via other steeringmechanisms) to bias the curveable cannula in the curved path. Energyand/or another diagnostic or therapeutic agent is then optionallydelivered to the treatment location.

In accordance with several embodiments, a method of treating back painis provided. In some embodiments, the method comprises identifying avertebral body for treatment (e.g., a target for treatment of chronicback pain). In some embodiments, the method comprises identifying atreatment zone, area or site within the inner cancellous bone region ofthe vertebral body. In some embodiments, the treatment zone, area orsite is within a posterior section of the vertebral body (e.g.,posterior to an anterior-posterior midline, within the area between 20%and 50% of the distance from the posterior wall of the vertebral body).In some embodiments, the treatment zone comprises a locationcorresponding to the mid-height of the vertebra from ananterior-posterior view. In some embodiments, a border of the treatmentzone is at least 1 cm (e.g., between 1-2 cm, 2-3 cm, 3-4 cm, or more)from the posterior wall of the vertebral body. In some embodiments, thetreatment zone is determined by measuring the distance from theposterior wall to the basivertebral foramen as a percentage of the totaldistance from the posterior wall to the anterior wall of the vertebralbody.

In some embodiments, identifying a treatment zone is performedpreoperatively using imaging methods such as magnetic resonance imaging(MRI) or computed tomography (CT) imaging modalities. In someembodiments, the treatment zone, site, or location corresponds to alocation that is about mid-height between the superior and inferiorendplate surfaces of the vertebral body (which may be identified byimaging methods from an anterior-posterior view). In some embodiments,the treatment zone, site or location is identified by measuring thedistance from the posterior wall of the vertebral body to thebasivertebral foramen from images (e.g., (e.g., anteroposterior and/orlateral MRI or CT images) of the vertebral body as a percentage of thetotal distance from the posterior wall to the anterior wall of thevertebral body. In some embodiments, inserting the neuromodulationdevice within the treatment zone is performed under visualization (e.g.,using fluoroscopy). In some embodiments, positioning a distal endportion of the neuromodulation device within the treatment zonecomprises positioning the distal end portion (and any active elementssuch as electrodes located at the distal end portion) at a locationcorresponding to the measured distance percentage described above. Insome embodiments, the percentage is a standardized distance percentagethat is not individually measured for the individual subject orvertebral body being treated. In some embodiments, the treatment zone,site, or location corresponds to a location at or proximate (e.g.,posterior to) a terminus of the basivertebral foramen.

In some embodiments, the method comprises inserting a curved cannulathrough the outer cortical bone region of the vertebral body and intothe inner cancellous bone region of the vertebral body. The curvedcannula can comprise a flexible catheter, tube, or other conduit havinga pre-curved or steerable distal end. The curved cannula may compriseNitinol, PEEK, or other thermoplastic, shape memory or resilientlydeformable material. In some embodiments, the method comprises insertinga neuromodulation device within the curved cannula. The neuromodulationdevice can comprise an energy delivery device, a fluid delivery device,or an agent delivery device. The fluid may or may not comprise an agent,such as a chemical agent. In one embodiment, the chemical agentcomprises a lytic agent.

In various embodiments, the energy delivery device is configured todeliver radiofrequency energy, microwave energy, light energy, thermalenergy, ultrasonic energy, and/or other forms of electromagnetic energy,and/or combinations of two or more thereof. In accordance with severalembodiments, the energy is configured to heat tissue within bone (e.g.,a vertebral body) sufficient to modulate (e.g., denervate, ablate)intraosseous nerves (e.g., basivertebral nerves or other nerves locatedpartially or fully within bone). In other embodiments, the energy isconfigured to treat tissue outside the spine, for example in non-spinaljoints or in non-orthopedic applications (e.g., cardiac, pulmonary,renal, or treatment of other organs and/or their surrounding nerves).The temperature of the energy may be in the range of between 40° C. and100° C., between 50° C. and 95° C., between 60° C. and 80° C., between75° C. and 95° C., between 80° C. and 90° C., overlapping rangesthereof, or any temperature between the recited ranges. In someembodiments, the temperature and length of treatment can be varied aslong as the thermal dose is sufficient to modulate (e.g., at leasttemporarily denervate, ablate, block, disrupt) the nerve. In someembodiments, the length of treatment (e.g., delivery of energy) rangesfrom about 5 to about 30 minutes (e.g., about 5 to 15 minutes, about 10to 20 minutes, about 15 to 25 minutes, about 20 to 30 minutes,overlapping ranges thereof, 15 minutes, or about any other length oftime between the recited ranges). In some embodiments, theneuromodulation device comprises a sensor to measure nerve conduction ofthe nerve at the treatment zone.

The energy delivery device may comprise one or more probes (e.g., aradiofrequency probe). In some embodiments, the probe comprises one ormore electrodes configured to generate a current to heat tissue withinbone. In one embodiment, the probe comprises a bipolar probe having twoelectrodes. The two electrodes may comprise an active electrode and areturn electrode. In one embodiment, the active electrode comprises atip electrode positioned at the distal tip of the radiofrequency probeand the return electrode comprises a ring electrode spaced proximallyfrom the active electrode with insulation material between the twoelectrodes. In one embodiment, the return electrode comprises a tipelectrode positioned at the distal tip of the probe (e.g., aradiofrequency probe) and the active electrode comprises a ringelectrode spaced proximally from the return electrode. The twoelectrodes may be spaced about 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm,8 mm, 9 mm or 1 cm apart. In various embodiments, the electrodescomprise cylindrical electrodes, tip electrodes, plate electrodes,curved electrodes, circular electrodes, or other shapes. In someembodiments, the electrodes comprise an electrode array. In variousembodiments, the frequency of the energy can be between about 100 kHzand 1 MHz, between 400 kHz and 600 kHz, between 300 kHz and 500 kHz,between 350 kHz and 600 kHz, between 450 kHz and 600 kHz, overlappingranges thereof, or any frequency within the recited ranges.

In one embodiment, the energy delivery device comprises an ultrasoundprobe having one or more ultrasound transducers. The ultrasound probemay be configured to deliver high-intensity focused ultrasonic energy,low-intensity ultrasonic energy or other forms of ultrasonic energysufficient to modulate the nerve. The ultrasound energy may be used forcavitation or non-cavitation. In one embodiment, the energy deliverydevice comprises a laser or light energy delivery device configured todeliver light energy sufficient to modulate the nerve. In oneembodiment, the energy delivery device is configured to deliverradiation sufficient to modulate the nerve. In one embodiment, theenergy delivery device comprises a microwave energy delivery devicecomprising one or more microwave antennas configured to delivermicrowave energy sufficient to effect modulation of the nerve.

In one embodiment, a fluid delivery device is used to effect atemperature change in a location in the disc. For example, the fluiddelivery device may be used to deliver a cryoablative fluid. In anotherembodiment, the fluid delivery device may be used to deliver a coolingfluid to cool a region in conjunction with a therapy that generatesheat. In some embodiments, a distal portion of the curved cannula isshaped so as to guide a distal end of the neuromodulation device towardsthe midline of the vertebral body (or other treatment area outside thespine). In some embodiments, a proximal end of the fluid delivery deviceis coupled to a fluid source or reservoir (e.g., syringe, fluid pump).In some embodiments, the fluid delivery device comprises a catheter,tube, sleeve, needle, cannula, wicking device, or other conduitconfigured to deliver fluid. The fluid may comprise neurolytic agents,chemotherapy agents, radioactive substances, medications, drugs,pharmaceuticals, alcohols, acids, solvents, cooling agents, nerveblocking agents, and/or other chemical agents.

In some embodiments, the method comprises advancing the distal end ofthe neuromodulation device out of a distal opening of said cannula andinto the inner cancellous bone region of the vertebral body or treatmentarea. The distal opening may be an axial opening or a radial opening. Insome embodiments, the method comprises positioning the distal end ofsaid neuromodulation device within, at or proximate the treatment zone,area site, or location of the vertebral body or treatment area.

In some embodiments, the method comprises effecting modulation of atleast a portion of a nerve (e.g., basivertebral nerve or intraosseousnerve) using the neuromodulation device. The modulation (e.g.,neuromodulation) can comprise partial or complete and/or temporary orpermanent blocking, disruption, denervation or ablation of the nerve. Invarious embodiments, the modulation comprises radiofrequency ablation,microwave energy ablation, chemical ablation, cryoablation, ultrasonicablation, laser ablation, thermal ablation, thermal heating, cooling,mechanical severing, neuromodulation, and/or stimulation of the nerve.In one embodiment, stimulation of the nerve is performed to block thetravel of signals indicative of pain. Stimulation may comprisemechanical, electrical, or electromechanical stimulation. Thestimulation may be continuous or pulsed.

In accordance with several embodiments, a method of treating pain (e.g.,back pain) is provided. In some embodiments, the method comprisesidentifying a treatment zone, such as a vertebral body for treatment(e.g., an identified source of pain or location likely to treat pain).In some embodiments, the treatment zone comprises a basivertebralresidence zone within which a portion of the basivertebral nerve (e.g.,main trunk, junction, terminus of basivertebral foramen, etc.) is likelyto reside. In some embodiments, the treatment zone is identified withoutknowing the precise location of the basivertebral nerve. In someembodiments, the method comprises identifying a treatment zone, site,region or location within the inner cancellous bone region within aposterior section of the vertebral body. The posterior section maycomprise a section posterior to an anterior-posterior midline or aregion within a distance between about 10% and about 50%, between about20% and about 50%, between about 10% and about 40% of the distance fromthe posterior wall. In some embodiments, the method comprises insertinga distal end portion of the neuromodulation device (e.g., energy and/orfluid delivery probe), and any active elements disposed thereon, withinor proximate the treatment zone. In some embodiments, the methodcomprises thermally inducing modulation of a function of a basivertebralnerve within the vertebral body with the energy delivery probe.

In some embodiments, the method comprises generating a curved pathwithin the inner cancellous bone region towards a midline of thevertebral body with a cannula having a pre-curved distal end portion tofacilitate access to the posterior section of the vertebral body. Insome embodiments, insertion of the neuromodulation device through acurved cannula allows for access straight through (e.g., concentricallythrough) the pedicle in a transpedicular approach instead of anoff-center access, which may be difficult for some levels of vertebraedue to anatomic constraints. In some embodiments, the method comprisesinserting the neuromodulation device within the curved path created bythe cannula. In some embodiments, the cannula is shaped so as to guide adistal end portion of the neuromodulation device towards the midline ofthe vertebral body. In some embodiments, the method comprises insertinga stylet within the cannula that is adapted to penetrate bone tissue ofthe vertebral body beyond the curved path created by the cannula.

In accordance with several embodiments, a method of therapeuticallyheating a vertebral body to treat back pain is provided, In someembodiments, the method comprises identifying a residence zone of abasivertebral nerve within the inner cancellous bone region of thevertebral body. In some embodiments, the method comprises inserting twoelectrodes into the vertebral body. In some embodiments, the methodcomprises positioning the two electrodes within or proximate theresidence zone. In some embodiments, the method comprises generating aheating zone between the two electrodes to heat the basivertebral nerve.For example, a first electrode may be activated to generate a currentbetween the first electrode and a second electrode. The current maygenerate heat within the bone tissue. The heating zone may comprise aninner resistive heating zone and an outer conductive heating zone. Insome embodiments, the heating zone is configured to have a radius ordiameter between about 0.5 cm and 2 cm (e.g., 0.5 cm, 0.6 cm, 0.7 cm,0.8 cm, 0.9 cm, 1 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm,1.7 cm, 1.8 cm, 1.9 cm, 2 cm). In accordance with several embodiments,forming heating zones (and in some cases, lesions) of a specific sizeand shape can be improved by adjusting parameters such as diameter andactive length of electrodes, initial and steady-state power input,length of treatment, and device control temperature.

In some embodiments, inserting two electrodes into the vertebral bodycomprises inserting a first energy delivery probe having a firstelectrode within the inner cancellous bone region and positioning asecond energy delivery probe having a second electrode within the innercancellous bone region. In some embodiments, inserting two electrodesinto the vertebral body comprises inserting a single energy deliveryprobe having two electrodes within the inner cancellous bone region.

In some embodiments, positioning the two electrodes within or proximatethe residence zone comprises positioning the electrodes at a locationsuch that a single heating treatment modulates (e.g., denervates,ablates) the entire basivertebral nerve system without requiringseparate downstream modulation (e.g., denervation, ablation) treatments.In some embodiments, positioning the two electrodes of within orproximate the residence zone comprises positioning the two electrodes tostraddle the residence zone. In some embodiments, positioning the twoelectrodes within or proximate the residence zone comprises positioninga first electrode on a first side of the vertebral body and positioninga second electrode on a second side of the vertebral body.

In accordance with several embodiments of the invention, methods andsystems allow for positioning of a treatment device in contact with orin close proximity to a basivertebral nerve without knowing the preciselocation of the basivertebral nerve. In attempting to place at least oneelectrode in close proximity to the BVN, the approaches disclosed in theteachings of the art are somewhat problematic. In particular, althoughthe location of the BVN is somewhat well known, the BVN is radiolucentand so its precise location can not be easily identified by an X-ray.Since the BVN is also extremely thin, knowingly placing the electrode inclose proximity to the BVN may be problematic in some cases. Moreover,in one embodiment, since certain RF electrodes appear to heat only afairly limited volume of bone, misplacement of the electrode vis-à-visthe BVN may result in heating a volume of bone that does not contain theBVN. “Close proximity” with regard to the intraosseous or basivertebralnerve can mean located at a position such that the nerve is modulatedupon activation of the neuromodulation device or delivery of fluid orother substances by the neuromodulation device.

For example, and now referring to FIGS. 20 and 21, there is provided arepresentation of a treatment scheme involving the placement of aconventional bipolar electrode device in close proximity to anintraosseous nerve (ION). In these figures, the ION is represented bythe solid line identified as ION, while the vertically-disposed dottedlines identify the edges of the zone within which the practitionerbelieves the ION likely resides (i.e., the ION residence zone, or“IRZ”). As shown in FIGS. 20 and 21, if the ION is substantially in thecenter of the ION residence zone, then placement of the bipolarelectrode either on the left hand boundary of the ION residence zone (asin FIG. 20) or substantially in the middle of the ION residence zone (asin FIG. 21) satisfactorily locates the electrodes in a region thatallows the current flowing from the electrodes to flow across the ION.In several embodiments, since the current flowing across the ION mayresistively and conductively heat the local bone tissue and the ION maybe heated to therapeutically beneficial temperatures, these scenariosmay provide beneficial treatment of the ION.

However, now referring to FIG. 22, if the ION is substantially at theright edge of the ION residence zone, then placement of the bipolarelectrodes on the left hand side of the ION residence zone fails tolocate the electrodes in a region that allows the current flowing fromthe electrodes to flow across the ION. Accordingly, current flowingacross the electrodes can not resistively heat the ION. Moreover, sincebone is a heat sink that may effectively limit the heat transport toabout 0.5 cm, the heat produced by the electrodes may be effectivelydissipated before it can reach the ION by conduction.

Similarly, now referring to FIG. 23, if the ION is substantially at theleft edge of the ION residence zone, then placement of the bipolarelectrodes in the middle of the ION residence zone fails to locate theelectrodes in a region that allows the current flowing from theelectrodes to flow across the ION. Again, current flowing across theelectrodes may not resistively heat the ION, and the heat sink qualityof bone may effectively dissipate the heat produced by the electrodesbefore it can reach the ION by conduction.

Moreover, even if the precise location of the BVN were known, it hasbeen found to be difficult to access the posterior portion of the BVNfrom a transpedicular approach with a substantially straight probe,especially for some levels of the vertebrae that have anatomicalconstraints.

Therefore, in accordance with several embodiments, the systems andmethods described herein allow the practitioner to heat thebasivertebral nerve without having to know the precise location of thebasivertebral nerve, and without having to precisely place the electrodetip next to the portion of the basivertebral nerve to be treated, whilestill allowing the practitioner to access the vertebral body straight(e.g., concentrically) through the pedicle.

The terms “modulation” or “neuromodulation”, as used herein, shall begiven their ordinary meaning and shall also include ablation, permanentdenervation, temporary denervation, disruption, blocking, inhibition,therapeutic stimulation, diagnostic stimulation, inhibition, necrosis,desensitization, or other effect on tissue. Neuromodulation shall referto modulation of a nerve (structurally and/or functionally) and/orneurotransmission. Modulation is not limited to nerves and may includeeffects on other tissue.

Several embodiments of the invention relate to the production of a largebut well-controlled heating zone within bone tissue to therapeuticallytreat (e.g., modulate) an ION within the heating zone. Other embodimentsprovide modulation of non-spinal tissue (e.g., nerves).

Now referring to FIGS. 24-25, there is provided a representation of anembodiment in which electrodes E₁ and E₂, respectively, disposed onprobes (not shown) treat (e.g., modulate) the ION. FIG. 24 provides aschematic representation of the electric field EF produced in the bonetissue by activation of the electrodes. In this case, the electric fieldis relatively thin. FIG. 25 provides a schematic representation of thetotal heating zone (THZ) produced by the electric field of FIG. 24including both an inner resistive heating zone IR (represented by opencircles) and an outer conductive heating zone OC (represented by closedcircles). In this case, the inner resistive zone is produced by thejoule heating of bone tissue disposed within the electric field EF,while the outer conductive zone is heated by conduction of heat from theresistive heating zone.

Still referring to FIG. 25, the positioning of two (e.g., an active andreturn) electrodes of an energy-transmitting device in a manner thatallows the electrodes to straddle the ION residence zone (IRZ) providesa large but well-controlled total heating zone (IR+OC) within bonetissue to therapeutically treat the ION within the heating zone. Sincethe total heating zone is large and the electrodes straddle the IRZ,there is a high level of confidence that a portion of the ION will bepresent within the total heating zone. Since the total heating zone iswell controlled, there is no danger (as with monopolar systems) thatcurrent flowing from the active electrode will undesirably affectcollateral tissue structures

Now referring to FIG. 26, if the ION is in fact substantially in thecenter of the ION residence zone, then placement of the two (e.g.,bipolar) electrodes in a manner that straddles the ION residence zoneallows the production of a total heating zone between the electrodesthat includes a portion of the ION therein.

Moreover, embodiments of the invention allow the practitioner totherapeutically treat the ION even when the ION is in fact located atthe edges of the ION residence zone IRZ. Now referring to FIGS. 27 and28, if the ION is located substantially at the right edge (as in FIG.27) or the left edge (as in FIG. 28) of the ION residence zone IRZ, thenplacement of the two (e.g., bipolar) electrodes in a manner thatstraddles the ION residence zone still allows the production of a totalheating zone between the electrodes that includes a portion of theactual ION therein.

Therefore, in one embodiment, the straddling of the ION residence zonesatisfactorily locates the electrodes so that the total heating zoneproduced by the electrode activation includes the ION irrespective ofthe actual location of the ION within the ION residence zone IRZ,thereby ensuring that the electrodes heat the ION to therapeuticallybeneficial temperatures.

Therefore, some embodiments provide a method of therapeutically treatinga bone having an intraosseous nerve ION defining first and second sidesof the bone, comprising inserting an energy device having an active anda return electrode into the bone, and placing the active electrode onthe first side of the bone and the return electrode on the second sideof the bone to define a total heating zone therebetween. A sufficientlyhigh frequency voltage may then be applied between the active and returnelectrodes to generate a current therebetween to resistively heat thetotal heating zone sufficient to denervate the ION.

Several embodiments provide a very controlled total heating zone whichexists substantially only between the paired electrodes. In accordancewith several embodiments, the consequent ability to both modulate theBVN with substantial certainty and to minimize the volume of bone tissueaffected by the heating appears to be novel in light of the conventionalbone-related technology.

Accordingly, some embodiments of the invention are advantageous becausethey allow the clinician to create a sufficiently large heating zone fortherapeutically treating the ION (e.g., BVN) without requiring directaccess to the ION. Some embodiments of the invention are particularlyadvantageous because such embodiments: (i) do not require knowing theprecise location of the ION, (ii) do not require directly accessing theION, and/or (iii) have a controlled heating profile that allows aclinician to avoid heating adjacent structures such as the healthyadjacent cancellous bone tissue, the spinal cord or opposing vertebralendplates.

In accordance with several embodiments, there is provided a method oftherapeutically treating a vertebral body having a BVN defining firstand second sides of the vertebral body In one embodiment, the methodcomprises determining a BVN residence zone within which the BVN likelyresides, the BVN residence zone having a first side and a second side,inserting an energy device having an active and a return electrode intothe vertebral body, placing the active electrode on the first side ofthe residence zone and the return electrode on the second side of theresidence zone to define a total heating zone therebetween, and applyinga sufficiently high frequency voltage between the active and returnelectrodes to generate a current therebetween to resistively heat thetotal heating zone to a temperature sufficient to denervate the BVN.

Further aspects of embodiments of the invention will be discussed in thefollowing portions of the specification. With respect to the drawings,elements from one figure may be combined with elements from the otherfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

Several embodiments of the invention will be more fully understood byreference to the following drawings which are for illustrative purposesonly:

FIG. 1 is a system for generating a curved path in bone according tocertain embodiments of the invention.

FIG. 2 is a sectional view of the system of FIG. 1.

FIG. 3 illustrates a sectioned view of a vertebral body with a pathbored through the cortical shell.

FIGS. 4A-4F illustrate a method for accessing the BVN with an embodimentof the system.

FIG. 5 shows an alternative system for generating a curved path in bone

FIG. 6 shows the system of FIG. 5 being installed in a vertebral body.

FIGS. 7A-7B show a curved stylet.

FIG. 8 illustrates a perspective view of a system for generating acurved path in bone.

FIG. 9 is an exploded view of the system of FIG. 8.

FIG. 10A-10E show schematic diagrams of the system of FIG. 8 at variousstages of deployment during a procedure.

FIG. 11 is a section view of the proximal end of the system of FIG. 8during introduction of the system into the body.

FIG. 12 is a side view of the distal end of the system of FIG. 8 duringintroduction of the system into the body.

FIG. 13 is a section view of the proximal end of the system of FIG. 8after deploying the curveable cannula into the body.

FIG. 14 is a side view of the distal end of the system of FIG. 8 afterdeploying the curveable cannula into the body.

FIG. 15 is a section view of the proximal end of the system of FIG. 8with the drive nut retracted.

FIG. 16 is a section view of the proximal end of the system of FIG. 8after deploying the probe into the body.

FIG. 17 is a side view of the distal end of the system of FIG. 8 afterdeploying the probe into the body.

FIGS. 18A and 18B are side views of the distal end of the system of FIG.8 with the curveable cannula in a stowed and deployed positionrespectively.

FIG. 19A illustrates a perspective view of an alternative system forgenerating a curved path in bone.

FIG. 19B illustrates the system of FIG. 19A in a deployed configuration.

FIGS. 20 and 21 depict the treatment of the BVN with a bipolarelectrode.

FIGS. 22 and 23 depict the difficulty of treating a BVN with a bipolarelectrode.

FIGS. 24 and 25, respectively, depict top views of an electric field anda heating zone produced within bone tissue.

FIGS. 26-28 depict the treatment of the BVN with a bipolar electrodeapparatus.

FIGS. 29A and 29B disclose anterior and upper cross-sectional views of astraddled ION that extends in a plane above the electrodes but withinthe total heating zone.

FIG. 30 is a cross-sectional anterior view of an embodiment in which thetotal heating zone has dumb-bell type resistive heating zones.

FIG. 31 depicts a top view of the treatment of the BVN with a bipolarelectrode apparatus wherein the distal ends of the probes are locatedsubstantially at the midline of the vertebral body.

FIG. 32 discloses cross-sections of components of a dual probeapparatus.

FIG. 33 discloses an embodiment in which a portion of the probe shaftacts as an electrode.

FIGS. 34-37 disclose four embodiments in which at least a portion of theelectrode faces thereof are disposed in a substantially parallelrelation.

FIG. 38 discloses a cross-sectional view of an apparatus in which thecannula has a bore having a distal bend and a lateral opening.

FIGS. 39A and 39B disclose cross-sectional views of an apparatus inwhich the cannula has a proximal bend.

FIGS. 40A and 40B disclose-cross-sectional views of an apparatus inwhich the probe has a pivoted portion containing an electrode.

FIG. 41 discloses a probe having reverse conical electrodes.

FIG. 42 discloses a probe having a plurality of active electrodes and acorresponding plurality of return electrodes.

FIG. 43 discloses a bipolar probe in which the return electrode has arelatively large surface area.

FIG. 44 presents a cross-sectional view of an articulated probe havingboth active and return electrodes.

FIG. 45 discloses the treatment of a posterior portion of the BVN with abipolar electrode apparatus.

FIGS. 46A-46D disclose respective top, anterior, lateral and perspectiveviews of the placement of a bipolar electrode apparatus within avertebral body.

FIGS. 47A and 47B show the location of thermocouples T0-T14 within thevertebral body.

FIGS. 48A-48C present the temperatures recorded by thermocouples T0-T14.

FIGS. 49A and 49B present the peak temperatures recorded bythermocouples T0-T14 within the vertebral body.

FIGS. 50A-50E present top views of a use of the articulated probe ofFIG. 44.

FIG. 51 presents a dual articulated needle embodiment.

DETAILED DESCRIPTION

Several embodiments of the invention are directed to systems and methodsto deploy and navigate a treatment instrument, such as a neuromodulationdevice (e.g., a radiofrequency (RF) bipolar probe, a microwave energydelivery device, a fluid or agent delivery device) within bone. Althoughthe systems and methods described herein are primarily directed tonavigating through the bone of a vertebral member of the spine, andparticularly to treat the basivertebral nerve (BVN) of a vertebralmember, the treatment may be applied to any nerve and/or to any tissuesegment of the body.

In accordance with several embodiments, the systems and methods oftreating back pain or facilitating neuromodulation of intraosseousnerves described herein can be performed without surgical resection,without general anesthesia, and/or with virtually no blood loss. In someembodiments, the systems and methods of treating back pain orfacilitating neuromodulation of intraosseous nerves described hereinfacilitate easy retreat if necessary. In accordance with severalembodiments of the invention, successful treatment can be performed inchallenging or difficult-to-access locations and access can be varieddepending on bone structure. One or more of these advantages also applyto treatment of tissue outside of the spine (e.g., other orthopedicapplications or other tissue).

Tube-in-Tube

FIGS. 1 and 2 illustrate an embodiment comprising a system or kit 10 forforming a path through bone. The system comprises a having a needletrocar 20 (the main body of the instrument set). The trocar 20 comprisesan elongate shaft 28 having a handle 24 at its proximal end 32 and acentral lumen 36 passing through to the distal end 22 of the trocar 20.The central lumen 36 is generally sized to allow the other instrumentsin the system 10 to be slideably introduced into the patient to atreatment region. System 10 further comprises a straight stylet 80having a sharp-tipped needle 84 at its distal end that is used with theneedle trocar 20 to create the initial path through the soft tissue andcortical shell to allow access to the cancellous bone, a curved cannula50 that is used to create/maintain the curved path within thebone/tissue. A straightening stylet 40 may be used to straighten out thecurve and load the curved cannula 50 into the needle trocar 20. A curvedstylet 60 may be used in conjunction with the curved cannula 50 tocreate the curved path within the bone/tissue, and a channeling stylet90 is used to create a working channel for a treatment device (such asRF probe 100) beyond the end of the curved path created by the curvedcannula 50.

The surgical devices and surgical systems described may be used todeliver numerous types of treatment devices to varying regions of thebody. Although the devices and systems are particularly useful innavigating through bone, in one embodiment they may also be used tonavigate through soft tissue, or through channels or lumens in the body,particularly where one lumen may branch from another lumen.

The following examples illustrate the system 10 applied to generating acurved bone path in the vertebral body, and more particularly forcreating a bone path via a transpedicular approach to access targetedregions in the spine. In particular, the system 10 may be used todeliver a treatment device to treat or ablate intraosseous nerves, andin particular that basivertebral nerve (BVN). Although the system andmethods provide significant benefit in accessing the BVN, in oneembodiment, the system 10 may similarly be used to create a bone path inany part of the body (such as the humerus, femur, pelvis, fibula, tibia,ulna, radius, etc.)

FIG. 3 illustrates a cross-sectional view of a vertebra 120. Recently,the existence of substantial intraosseous nerves 122 and nerve branches130 within human vertebral bodies (basivertebral nerves) has beenidentified. The basivertebral nerve 122 has, at least one exit 142 pointat a location along the nerve 122 where the nerve 122 exits thevertebral body 126 into the vertebral foramen 132. Minimally invasiveinterventional treatments for lower back pain is a promising alternativeto existing non-surgical conservative therapy or spinal surgerytreatments, including spinal fusion. The basivertebral nerve may provideinnervation to the trabecular bone of the vertebral body. Thebasivertebral nerves accompany the basivertebral vessels that enter thevertebrae through the large posterior neurovascular foramen. Thebasivertebral nerves may comprise segments having lengths between 5 and8 mm and diameters of 0.25 to 0.5 mm. The basivertebral nerve isbelieved to conduct pain receptive signals from intraosseous sources.Accordingly, modulation (e.g., defunctionalization, ablation) of thebasivertebral nerve is provided in several embodiments herein to reducechronic or acute back pain.

In accordance with several embodiments, the basivertebral nerves are at,or in close proximity to, the exit point 142. In some embodiments, theexit point 142 is the location along the basivertebral nerve where thebasivertebral nerve exits the vertebra. Thus, the target region of theBVN 122 is located within the cancellous portion 124 of the bone (i.e.,to the interior of the outer cortical bone region 128), and proximal tothe junction J of the BVN 122 having a plurality of branches 130.Treatment in this target region is advantageous because only a singleportion of the BVN 122 need be effectively treated to modulate (e.g.,denervate or otherwise affect the entire BVN system. Treatment, inaccordance with one embodiment, can be effectuated by focusing in theregion of the vertebral body located between 60% (point A) and 90%(point B) of the distance between the anterior and posterior ends of thevertebral body. In some embodiments, treatment is located at orproximate (e.g., posterior to) the junction J. In some embodiments,treatment of the BVN 122 in locations more downstream than the junctionJ requires the denervation of each branch 130. The target region may beidentified or determined by pre-operative imaging, such as from MRI orCT images. In various embodiments, treatment can be effectuated byfocusing in the region of the vertebral body located at a region that ismore than 1 cm from the outer cortical wall of the vertebral body,within a region that is centered at or about 50% of the distance fromthe posterior outer wall of the vertebral body to the anterior outerwall, and/or within a region that is between 10% and 90% (e.g., betweenabout 10% and about 60%, between about 5% and about 65%, between about10% and about 55%, or overlapping ranges thereof) of the distance fromthe posterior outer wall of the vertebral body to the anterior outerwall.

In various embodiments, the junction J is located at a location of theterminus of the vertebral foramen, at the junction between a main trunkof the BVN 122 and the initial downstream branches, at a locationcorresponding to a junction between at least one of the initialdownstream branches and its respective sub-branches, or other locationsalong the BVN 122.

In one approach for accessing the BVN, the patient's skin is penetratedwith a surgical instrument which is then used to access the desiredbasivertebral nerves, i.e., percutaneously. In one embodiment, atranspedicular approach is used for penetrating the vertebral cortex toaccess the BVN 122. A passageway 140 is created between the transverseprocess 134 and spinous process 136 through the pedicle 138 into thecancellous bone region 124 of the vertebral body 126 to access a regionat or near the base of the nerve 122. In one embodiment, apostereolateral approach (not shown) may also be used for accessing thenerve. The transpedicular approach, postereolateral approach,basivetebral foramen approach, and other approaches are described inmore detail in U.S. Pat. No. 6,699,242, herein incorporated by referencein its entirety.

FIGS. 4A-F illustrate a method for accessing the BVN with the system 10.First, the straight stylet 80 is inserted in aperture 26 at the proximalend 32 of needle trocar 20. The straight stylet 80 is advanced down thecentral lumen 36 (see FIG. 2) of the trocar 20 until the proximal stop82 abuts against handle 24 of the trocar 20, at which point the distaltip 84 of straight stylet protrudes out of the distal end 22 of thetrocar 20. In accordance with several embodiments, the tip 84 of thestraight stylet 80 comprises a sharp tip for piercing soft tissue andbone.

Referring now to FIG. 4A, in some embodiments, the assembly (trocar 20and straight stylet 80) is advanced through soft tissue to the surfaceof the bone. Once the proper alignment is determined, the assembly maybe advanced through the cortical shell of pedicle 138 and into thecancellous interior 124 of the bone.

In some embodiments, after the proper depth is achieved, the straightstylet 80 is removed from the trocar 20, while the trocar 20 remainsstationary within the vertebra 120. The straightening stylet 40 may beinserted into proximal aperture 52 (see FIG. 2) of the curved cannula 50and advanced along the central lumen of the curved cannula 50 until thestop 42 of the stylet 40 abuts up to the proximal end of the curvedcannula. In some embodiments, this forces the distal tip of the straightstylet through the curved section 56 of the curved cannula 50 tostraighten out the curve 56. In some embodiments, the straight styletcomprises a hard, noncompliant material and the distal end 56 of thecurved cannula 50 a compliant, yet memory retaining material (e.g.Nitinol, formed PEEK, etc.) such that the curved 56 section yields tothe rigidity of the straightening stylet 40 when installed, yet retainsits original curved shape when the stylet 40 is removed.

As shown in FIG. 4B, once the straightening stylet 40 is secure and thecurved cannula 50 is straight, they may be inserted together into theneedle trocar 20 and secured. Proper alignment (e.g. prevent rotation,orient curve direction during deployment) may be maintained by aligninga flat on the upper portion 58 of the curved cannula 50 to an alignmentpin secured perpendicularly into the needle trocar 20 handle 24. Otheralignment elements may also be used (e.g., visual indicia such as lines,text, shapes, orientations, or coloring). In some embodiments, once thecurved cannula 50 is secure, the straightening stylet 40 is removed,while the curved cannula 50 remains stationary within the trocar 20.

Referring to FIG. 4C, the curved stylet 60 can then straightened out bysliding the small tube 68 proximally to distally on its shaft towardsthe distal tip 64 or from the distal tip 64 proximally on its shafttowards the proximal end 62. In some embodiments, once the curved distaltip 66 is straightened out and fully retracted inside the small tube 68,the curved stylet 60 is inserted into the proximal aperture 52 of thecurved cannula 50, which still resides inside the needle trocar 20. Asthe curved stylet 60 is advanced into the curved cannula 50, the smalltube 68 may be met by a stop 55 (see FIG. 4C). As the curved stylet 60continues to advance, the small tube 68 may be held inside the handle ofthe curved cannula 50. This can allow the curve of the stylet 60 to beexposed inside the curved cannula 50. To create the maximum force, thecurve of the two parts (50 & 60) may be aligned. To facilitatealignment, the cap on the curved stylet 60 can have an alignment pin 70which engages with alignment notch 52 on the proximal end of the curvedcannula 50. Other alignment elements may also be used (e.g., visualindicia such as lines, text, shapes, orientations, or coloring).

Once the stylet 60 is fully seated and aligned with the curved cannula50, the tip of the curved stylet 60 may protrude from the tip of thecurved cannula 50 by about 1/16 to 3/16 inches. This protrusion can helpto drive the curve in the direction of its orientation duringdeployment.

Referring now to FIG. 4D, with the curved stylet 60 and the curvedcannula 50 engaged, the locking nut 58 at the top of the curved cannula50 may be rotated counter clockwise to allow the cannula 50 and stylet60 to be advanced with relation to the needle trocar 20 such that theproximal end 52 about against 58, advancing the curved cannula 50 andstylet 60 beyond the distal opening of trocar 20 to generate a curvedpath in the cancellous bone region 124. As the curved cannula 50 andstylet 60 are advanced they can curve at a radius of 0.4 to 1.0 inchesthrough cancellous bone and arc to an angle between approximately 0° toapproximately 180° (e.g., from approximately 5° to approximately 110°,from approximately 45° to approximately 110°, from approximately 15° toapproximately 145°, from approximately 30° to approximately 120°, fromapproximately 60° to approximately 90°, from approximately 10° toapproximately 45°, overlapping ranges thereof, or any angle within therecited ranges). Once the curved cannula 50 and stylet 60 are deployedto the intended angle, the locking nut at the top of the curved cannula50 may be engaged with the needle trocar 20 to stop any additionaladvancement of the curved stylet cannula assembly.

Referring to FIGS. 7A-7B illustrate the tip of a curved stylet 60, whichhas been formed with two angles. To help the curve deployment in theproper direction, the curve 66 of the curved stylet 60 may be shaped ina predetermined orientation. The angle on the inside of the curve 72 maybe less than the angle on the outside of the curve 74. This disparity inangles helps the stylet cannula assembly (collectively 50, 60) curve inthe bone as bone pushes against outside curve face 74, thereby ensuringthe curve radius is maintained during deployment, according to oneembodiment.

Referring now to FIG. 4E, the curved stylet 60 may then be removed andreplaced by the channeling stylet 90. The tip 94 of the channelingstylet 90 may be advanced beyond the end 54 of the curved cannula 50towards the intended target treatment zone.

Referring now to FIG. 4F, in some embodiments, once the channelingstylet 90 reaches the target treatment zone, it is removed, therebycreating a working channel 146. In some embodiments, channel 140generally has a first section 142 that crosses the cortical bone of thepedicle 138, followed by a curved path 144. These sections may beoccupied by curved cannula 50 such that a treatment device fed throughthe cannula 50 will have to follow the curve of the cannula 50 and notveer off in another direction. The channel 140 may further comprise thelinear extension 146 in the cancellous bone 124 to further advance thetreatment device toward the treatment site T. In some embodiments, thetreatment site T corresponds to a location of a terminus of the nerve122 (e.g., terminus of the basivertebral foramen or the junction betweena main trunk of the basivertebral nerve and its sub-branches). In someembodiments, the treatment site or location T is identified withoutknowing the precise location of the basivertebral nerve 122.

With the trocar 20 and curved cannula 50 still in place, a treatmentdevice (e.g. treatment probe 100 shown in FIG. 2) with an active element102 on the distal end 104 of elongate flexible catheter 110 may bedelivered to the target treatment location T to perform a localizedtreatment. In some embodiments, the target treatment location T isidentified prior to introduction of the trocar 20 by magnetic resonance(MR) imaging, computed tomography (CT) imaging, or other imagingmodalities. The introduction of the trocar 20, curved cannula 50,treatment device, and/or other instruments can be visualized in realtime using fluoroscopic or other imaging to ensure proper introductionand orientation within the target treatment location. In accordance withseveral embodiments, the treatment (e.g., neuromodulation) can beperformed at multiple levels of vertebrae (simultaneously orsequentially with one, two, three or more treatment devices). The levelsmay be adjacent or spaced apart. For example, treatments can beperformed at the L4 and L5 levels, at the L3-L5 levels, at the L5 and S1levels, or at other combinations of lumbar, sacral, cervical or thoracicvertebral levels. In some embodiments, a single treatment system ordevice (e.g., a generator and one or more radio frequency probes) ormultiple treatment systems or devices (e.g., two or more generators eachwith one, two, three or more radiofrequency probes) are used toadminister the treatment. In one embodiment, multiple treatment probescan be daisy-chained or otherwise reversibly or integrally coupled to(or integral with) each other and/or to a single generator or otherenergy generation module to simultaneously treat multiple levels ofvertebrae that are spaced apart. A “y” shaped device may be used in someembodiments. In various embodiments, the treatment devices comprise one,two, three or more energy sources (e.g., electrodes) that can beconnected by one or more connection members or elements to space theenergy sources apart to simultaneously treat multiple levels ofvertebrae. Simultaneous treatment of two or more vertebrae may betreated with radiofrequency or other therapeutic modalities (ultrasound,radiation, steam, microwave, laser, cryoablation, etc.). Differenttherapeutic modalities or different energy levels of the sametherapeutic modality that work simultaneously are provided in someembodiments.

In one embodiment, the active element 102 is delivered to the treatmentsite and activated to deliver therapeutic treatment energy. In variousembodiments, the treatment device comprises a probe, catheter, antenna,wire, tube, needle, cannula, sleeve, or conduit. The treatment devicemay comprise an RF delivery probe having bipolar electrodes 106 and 108that deliver a therapeutic level of heating (e.g., thermal dose) tomodulate (e.g., stimulate or ablate) at least a portion of the nerve122.

In some embodiments, the treatment device comprises a microwave energydelivery device comprising one or more antennas. In some embodiments,the treatment device comprises a chemical ablation or cryoablationdevice comprising a fluid conduit for delivery (e.g., injection) offluids, chemicals or agents (e.g., neurolytic agents) capable ofablating, stimulating, denervating, blocking, disrupting, or otherwisemodulating nerves. In some embodiments, the treatment device comprisesan ultrasound delivery device having one or more transducers or a laserenergy delivery device comprising one or more light delivery elements(e.g., lasers, such as fiber optic lasers or vertical cavity surfaceemitting lasers (VCSELs), or light emitting diodes (LEDs)).

According to several embodiments of the invention, many treatmentmodalities can be delivered to the treatment site for modulation ofnerves or other tissue (e.g., neuromodulation, ablation, temporary orpermanent denervation, stimulation, inhibition, blocking, disruption, ormonitoring). For example, treatment may be affected by monopolar ortripolar RF, ultrasound, radiation, steam, microwave, laser, or otherheating means. These modalities may be delivered to the treatment sitethrough one or more of the embodiments of systems and/or methodsdisclosed herein, and treatment applied such that the nerve is heated tothe desired level for the desired duration (e.g., a sufficient thermaldose is applied) to affect stimulation, denervation, ablation or thedesired therapeutic effect.

For example, the ultrasonic energy can be controlled by dosing, pulsingor frequency selection to achieve the desired heating level for thedesired duration. Similarly, microwave treatment may be applied using amicrowave energy delivery catheter and/or one or more antennas.Microwaves may be produced with a frequency in the range of 300 GHz to300 MHz, between 1 GHz and 5 GHz, between 2 GHz and 10 GHz, between 10GHZ and 100 GHz, 100 GHz and 300 GHz, between 50 GHz and 200 GHz,between 200 GHz and 300 GHz, or overlapping ranges thereof. Pulses ofbetween 1-5 seconds, between 2-3 seconds, between 0.5 seconds-2 seconds,between 4-5 seconds, between 5-10 seconds, between 10-30 seconds, oroverlapping ranges between, in duration may be generated. In someembodiments, a single pulse, 1-3 pulses, 2-4 pulses, 3-8 pulses, 8-20pulses, or overlapping ranges between, may be generated.

Radiation therapy may use radiation sources comprising any one of anumber of different types, such as, but not limited to, particle beam(proton beam therapy), cobalt-60 based (photon or gamma-ray source suchas that found in the GammaKnife), or linear accelerator based (e.g.,linac source). The dose of radiation delivered to the patient willtypically range between 10 Gy and 70 Gy. However, because the treatmentregion is contained within the large bony mass of the vertebral body,higher doses may be contemplated, as there is little risk to surroundingtissues that are more vulnerable. The dose may be varied based on thetreatment volume, or other variables such as treatment time and doseconcentration. A prescription of 35 instances of a 2 Gy dose might bereplaced by 15 instances of a 3 Gy dose, a technique known as“hypofractionation.” Taken to its logical extreme, this might bereplaced with a single 45 Gy dose if the dosage delivered to healthytissue can be reduced significantly. An identification dose may in someembodiments be used prior to the treatment dose, for example, to elicitsome response form the patient relating to the patient's pain. Theidentification dose is generally a much smaller dose than treatment doseTD, so as not to damage healthy tissue. An exemplary dose may range from0.5Gy to 5 Gy. However, this range may also change based onconsiderations such as anatomy, patient, etc.

Additionally or alternatively, the treatment device may comprise a fluidor agent delivery catheter that deposits an agent or fluid, e.g. bonecement, phenol, alcohol, neurotoxin, inhibitory or stimulatory drug,chemical, or medicament, for neuroablation or permanent or temporarydenervation, or other therapeutic agent, to the treatment site orlocation T. Growth factors, stein cells, gene therapy or otherbiological therapeutic agents may also be delivered.

In some embodiments, cryogenic cooling may be delivered for localizedtreatment of the BVN or an intraosseous nerve using, for example, liquidnitrogen, liquid nitrous oxide, liquid air, or argon gas. Cryotherapymay be delivered in one or more freeze cycles. In several embodiments,two freeze-thaw cycles are used. In some embodiments, 3-5 freeze-thawcycles are used. In some embodiments, a single freeze-thaw cycle is usedIn some embodiments, a desired temperature of the tissue is −40° C. to−50° C., −20° C. to −40° C., −35° C. to −45° C., −50° C. to −80° C., oroverlapping ranges thereof. The desired temperature may be maintainedfor 5-20 minutes, 10-15 minutes, or greater than 10 minutes, dependingon the temperature and thermal dose desired. Furthermore, treatment maybe effected by any mechanical destruction and or removal means capableof severing or denervating the BVN. For example, a cutting blade, bur,electrocautery knife or mechanically actuated cutter typically used inthe art of orthoscopic surgery may be used to effect denervation of theBVN.

In addition to or separate from treating (e.g., modulating) the BVN oran intraosseous nerve, a sensor may be delivered to the region topreoperatively or postoperatively measure nerve conduction at thetreatment region. In this configuration, the sensor may be delivered ona distal tip of a flexible probe that may or may not have treatmentelements as well.

In accordance with several embodiments, the goal of the treatment may beablation, or necrosis of the target nerve or tissue, or some lesserdegree of treatment to denervate the BVN. For example, the treatmentenergy or frequency may be just sufficient to stimulate the nerve toblock the nerve from transmitting signals (e.g. signals indicating pain)without ablation or necrosis of the nerve. The modulation may betemporary or permanent.

In several embodiments, the therapeutic modalities described herein(including energy or agent delivery) modulates neurotransmission (e.g.,neurotransmitter synthesis, release, degradation and/or receptorfunction, etc.). In some embodiments, signals of nociception areaffected. Effects on neurokinin A, neuropeptide Y, substance P,serotonin and/or other signaling pathways are provided in someembodiments. Calcium and/or sodium channel effects are provided in oneembodiment. In some embodiments, G-protein coupled receptors areaffected.

Once the treatment is complete, the probe 100 may be withdrawn. Thecurved cannula 50 may then be withdrawn into the needle trocar 20. Theneedle trocar 20 with the curved cannula 50 may then be removed and theaccess site may be closed as prescribed by the physician or othermedical professional.

In the above system 10, the design of the curves 56 and 66 of the curvedcannula 50 and curved stylet 60 is such that a flexible element (e.g.,distal portion of the treatment device) can navigate through the angularrange of deployment of the curved cannula 50 (e.g., Nitinol or othermaterial tube). The curved cannula 50 allows the flexible element tonavigate through a curve within bone without veering off towards anunintended direction. Cancellous bone density varies from person toperson. Therefore, creating a curved channel within varying densitycancellous bone 124 will generally not predictably or accurately supportand contain the treatment device as it tries to navigate the curvedchannel.

With the system 10, the treatment device 100 is deployed into the bonethrough the curved cannula 50 (e.g., Nitinol tube), which supports theflexible element (e.g., distal portion of the treatment device) as ittraverses through the curve. When it departs from the tube, it will doso in a linear direction along path 146 towards the target zone. Inaccordance with several embodiments, this advantageously allows the userto predictably and accurately deploy the treatment device towards thetarget zone or location T regardless of the density of the cancellousbone.

In some embodiments, a radius of curvature that is smaller than thatwhich can be achieved with a large diameter Nitinol tube may beadvantageous. To achieve this, the curved portion of the curved cannula50 may take one of several forms. In one embodiment, the curved cannula50 is formed from a rigid polymer (e.g., formed PEEK) that can be heatset in a particular curve. If the polymer was unable to hold the desiredcurve, an additional stylet (e.g. curved stylet 60) of Nitinol, flexiblestainless steel, shape memory material, metallic or metallic-basedmaterial, or other appropriate material, may also be used in conjunctionwith the polymer tube to achieve the desired curve. In some embodiments,the stylet comprises a braided tube, rod, or wire. In some embodiments,the stylet comprises a non-braided tube, rod, or wire, or combinationsthereof. This proposed combination of material may encompass any numberor variety of materials in multiple different diameters to achieve thedesired curve. These combinations only need to ensure that the finaloutside element (e.g. trocar 20) be “disengageable” from the internalelements and have an inner diameter sufficient to allow the desiredtreatment device 100 to pass to the treatment region T. In accordancewith several embodiments, the treatment region T is in a posteriorsection (e.g., posterior to a midline) of the vertebral body. Thetreatment region T may correspond to an expected location of a terminusof a basivertebral foramen.

In one embodiment, the curved cannula 50 may comprise a Nitinol, shapememory material, stainless steel or other metallic tube having a patternof reliefs or cuts (not shown) in the wall of the tube (particularly onthe outer radius of the bend). The pattern of cuts or reliefs couldallow the tube to bend into a radius tighter than a solid tube couldwithout compromising the integrity of the tubing wall. The curvedportion of the curved cannula 50 may comprise a different material thanthe main body of the curved cannula or the same material.

FIG. 5 illustrates a second embodiment of the system or kit 200 that maybe used to reduce the number of steps required for the procedure. Thesecond embodiment includes a needle trocar 20, straightening stylet 40,used with the needle trocar 20 and the curved cannula 50 to create theinitial path through the soft tissue and cortical shell to allow accessto the cancellous bone, curved stylet 60 used in conjunction with thecurved cannula 50 to create the curved path within the bone/tissue, andchanneling stylet 90 used to create a working channel for a treatmentdevice (e.g., probe) beyond the end of the curved path created by thecurved stylet.

In an embodiment of the method, the straightening stylet 40 is insertedinto the curved cannula 50 and secured. In this embodiment, thestraightening stylet 40 has a sharp tip 46 designed to penetrate bone.Once the straightening stylet 40 is secure and the curved cannula 50 isstraight, they are inserted into the needle trocar 20 and secured. Intone embodiment, the curved cannula 50 and straightening stylet 40 areinserted into the shaft 28 of the trocar 20 only as far as to have sharptip 46 of the straightening stylet 40 protrude from the distal end 22 ofthe trocar 20. Proper alignment is maintained by aligning a flat on theupper portion of the curved cannula 50 with a pin securedperpendicularly into the needle trocar 20 handle. Other alignmentelements may also be used (e.g., visual indicia such as lines, text,shapes, orientations, or coloring).

Referring now to FIG. 6, once the curved cannula 50 is secure, theassembly (trocar 20, curved cannula 50, and straightening stylet 40) maybe advanced through soft tissue to the surface of the bone. Afterfinding the proper alignment at the pedicle 138 of vertebra 120, theassembly (trocar 20, curved cannula 50, and straightening stylet 40) maybe advanced through the cortical shell 128 and into the cancellousinterior 124 of the bone.

After the proper depth is achieved, the straightening stylet 40 may beremoved. The curved stylet 60 may then be straightened out by slidingthe small tube 68 on its shaft towards the distal tip 64. In someembodiments, the curved distal tip 66 is straightened out and fullyretracted inside the small tube 68, and then the curved stylet 60 isinserted into the curved cannula 50, which still resides inside theneedle trocar 20. Once the curved stylet 60 is inserted into the curvedcannula 50, the small tube 68 may be met by a stop 55 (see FIG. 4C). Asthe curved stylet 60 continues to advance, the small tube 68 may be heldinside the handle of the curved cannula 50. This can allow the curve ofthe stylet 60 to be exposed inside the curved cannula 50.

To create a maximum force, it may be advantageous that the curves of thetwo parts (50 & 60) are aligned. To ensure alignment, the cap on thecurved stylet 60 may have an alignment pin, which engages with a notchon the top of the curved cannula 50. Other alignment elements may alsobe used (e.g., visual indicia such as lines, text, shapes, orientations,or coloring).

When the stylet 60 is fully seated and aligned with the curved cannula50, the tip of the curved stylet 60 may protrude from the tip of thecurved cannula 50 by about 1/16 to 3/16 inches. This protrusion can helpto drive the curved cannula 50 in the direction of its orientationduring deployment. Once the curved stylet 60 and the curved cannula 50are engaged, the lock nut at the top of the curved cannula 50 may berotated counter clockwise to allow the cannula 50 and stylet 60 to beadvanced with relation to the needle trocar 20 (as shown in FIG. 4D). Asthe curved cannula and stylet are advanced they generate a curved pathtoward the treatment location T. Once the curved cannula 50 and stylet60 are deployed to the intended angle, the lock nut at the top of thecurved cannula 50 may be engaged with the needle trocar 20 to stop anyadditional advancement of the curved stylet cannula assembly.

The curved stylet 60 may then be removed and replaced by the channelingstylet 90. In some embodiments, the channeling stylet 90 is advancedbeyond the end of the curved cannula 50 (see FIG. 4E) towards theintended target treatment zone, thereby creating a working channel forthe active element to be inserted. Once the channeling stylet 80 reachesthe target treatment zone, it can be removed and replaced by thetreatment device 100, which can be delivered to the treatment site T andactivated.

Once the treatment is complete, the treatment device 100 can bewithdrawn. In some embodiments, the curved cannula 50 is then withdrawninto the needle trocar 20. The needle trocar 20 with the curved cannula50 can then be removed and the access site can be closed as prescribedby the physician or other medical professional.

FIGS. 7A and 7B illustrate detailed views of a Nitinol or other shapememory material wire, rod or tube for the curved stylet 60 (proximal endnot shown). The wire comprises a shaft 78 having constant diameter D anda length L_(s) that may vary according to the application and desireddepth to the treatment location. The wire has a preformed distal tipthat is curved to have a radius r that redirects the distal tip 64 at anangle θ with the shaft. As shown in FIG. 7A, angle θ is shown to beapproximately 110°. However, in one embodiment, the preformed tip mayhave an angle ranging from a few degrees (slight deflection off axis),to up to 180° (e.g. directing back toward the proximal end).

As shown in FIG. 7B detailing the distal tip 64, the tip may have adistal extension L_(T) that extends away from the shaft 78. To promotechanneling along a path that follows radius r, the distal tip 64 isconfigured with dual-plane bevels 74 and 72. Plane 74 is offset at angleβ, and plane 72 is offset at angle α. This configuration can allow forthe stylet and/or curved cannula to travel through bone in a pathcorrelating to the specified curve in the stylet and/or cannula.

In the example illustrated in FIGS. 7A and 7B, the curved stylet 60 mayhave a shaft length L_(S) of approximately 2-5 inches (e.g., 3.6 in.),diameter D of approximately 0.02-0.06 inches (e.g., 0.040 in.), and adistal tip length L_(T) of about 0.08-0.16 inches (e.g., 0.125 in.), aradius r of about 0.2-0.6 inches (e.g., 0.4 in.), and angle β=35° andangle α=31°. The angles may vary by up to about 10 degrees, up to 15degrees, or up to 20 degrees in either direction. It should be notedthat the above dimensions are for illustration only, and may varydepending on the anatomy and tissue type. For example, the modulationdevices disclosed herein can be used, in some embodiments, to modulatenerves or treat tissue in other areas of the spine. Non-spinalapplications are also contemplated. For example, denervation of renalnerves, cardiac ablation and other non-spinal treatment can beaccomplished according to several embodiments described herein.

Any of the embodiments described herein may be provided as a kit ofinstruments to treat different regions of the body. For example, thelocation, orientation and angle of the treatment device with respect tothe trocar 20 may be varied by providing a set of instruments at varyingincrements. This may be achieved by varying the curvature (56, 66) inthe curved cannula 50 and curved stylet 60. The curvature may be variedby varying the radius of curvature r, the insertion depth (shaft lengthL_(S) and tip length L_(T), and/or the final exit angle θ with respectto the trocar 20 central bore. Thus, the physician or other clinicianmay select a different kit for treating a lumber spine segment asopposed to a cervical spine segment, as the anatomy will dictate thepath that needs to be channeled.

Thus, when treating different spine segments, a set out of the kit maybe selected to match the vertebra (or other region being treated). Forexample, delivering the treatment device at or near the BVN junction orterminus for a lumbar vertebra may have a different angle than for asacral or cervical vertebra, and may vary from patient to patient. Theset may be selected from the kit intraoperatively, or from a pre-surgerydiagnostic evaluation (e.g. radiographic imaging of the target region).

Tube in Windowed Tube

FIGS. 8-18B illustrate a system 201 for generating a curved path inbone. FIG. 8 shows a perspective view of system 201 in a configurationready for deployment within a patient's body. System 201 comprises anintroducer/trocar 210 having a proximal end housing 202 coupled to anelongate delivery tube 204. The distal end tip 208 has a sharpenedand/or beveled tip to facilitate entry into and delivery through atleast a portion of a bony mass such as the vertebral body. The proximalend of the assembly (e.g., drive nut 270), may comprise a hard, rigidmaterial to allow the trocar 210 to be tapped into place with a malletor the like.

The elongate delivery tube 204 comprises a laterally positioned radialopening or window 212 disposed just proximal or at the distal tip 208.The window 212 provides radial access from the central channel 218 oftube 204 so that an instrument or probe (e.g. probe 250 distal end) maybe delivered at an angle (e.g. non-axial) with respect to the tube axisor central channel 218.

FIG. 9 illustrates an exploded view of system 201 prior to deliverywithin a patient. While it is preferred that the trocar 210 isintroduced to a location near the target treatment site as a wholeassembly shown in FIG. 8, in one embodiment, the trocar may beintroduced to the location by itself, with the additional componentsbeing positioned once the trocar 210 is in place. In such aconfiguration, a stylet (not shown) may be positioned down the centralchannel 218 of the trocar 204 so as to block the aperture 212 from bonefragments or other tissue matter entering in channel 218. The stylet mayhave a hard, widened proximal end to allow the trocar 210 to be tappedinto place.

The proximal end 206 of trocar housing 202 comprises acentrally-located, counter-bore or recess 216 that is in communicationwith trocar channel 218. Trocar recess 216 allows placement andreciprocation of curveable cannula 230 within the trocar recess 216 andtrocar central channel 218. The curveable cannula 230 may be held inplace at a specified location within the trocar recess 216 via a stopnut 240 that is threaded about proximal body 246 of the curveablecannula 230. The curveable cannula 230 also comprises a central recess268 within proximal body 246 that is centrally aligned with cannulachannel 245. Central recess 268 and cannula channel 245 are configuredto receive and allow reciprocation of probe 250, which is threaded intodrive nut 270. In several embodiments, the drive nut 270 comprises ahardened proximal surface suitable for applying an impact force toadvance one or more of the trocar, curveable cannula, or probe throughbone.

FIGS. 10A-10E schematically illustrate the system 201 in various stagesof deployment. FIGS. 11, 13, 15 and 16 illustrate section views of theproximal end of system 201 through the various stages embodied in FIGS.10A-E. Correspondingly, FIGS. 12 and 14, illustrate close-up views ofthe distal end of system 201 through various the stages embodied inFIGS. 10A-10E.

FIG. 11 illustrates a sectional view of the proximal end of system 201in an un-deployed state prior to or during insertion of the trocar 210to the desired treatment location in the patient. For delivery into avertebral body 120 (e.g. to access the BVN), the trocar 210 may bedelivered through pedicle 138 via channel 140 (as shown in FIG. 3).Channel 140 may be a pre-drilled hole, or may be generated by insertionof the sharpened tip 208 into the bone. To facilitate insertion, theproximal surface 292 of cap 290 of the drive nut 270 may comprise arigid material (e.g. stainless steel or the like) so that a mallet orsimilar device may strike surface 292 to tap the trocar body 204 intoplace.

During insertion of the trocar 210, the stop nut 240 may be threadeddistally along external threads 248 of the proximal body 246 of thecurveable cannula 230 to restrict motion of the cannula 230 distallydown trocar recess 216. This restrained motion may keep the distal end232 of the cannula 230 from prematurely deploying while the trocar 210is being delivered.

In accordance with several embodiments, the distal end of the curveablecannula is deformable so as to be delivered in a straight configurationthrough the trocar and deployed in a curved configuration outward fromthe radial opening at an angle with respect to the central axis. Asshown in FIG. 12, the distal tip 233 of the curveable cannula 230comprises a series of tubular mating links 234 each having a centralbore to provide a continuous cannula channel 245 along with cannula tube244. The mating links 234 may be configured to cause the distal tip 233of the curveable cannula to articulate into a curved shape and besteerable. Cannula channel 245 extends from central cannula recess 268of the proximal body 246 to the distal link 232 at tip 233. Distal link232 comprises a beveled tip 233 to facilitate the curveable cannula 230generating a path through bone as detailed below. Distal link 232 mayalso comprise a hard material (e.g. stainless steel, thermoplastic, orthe like) to provide a rigid leading edge for the curveable cannula 230.

The mating links 234 are held together with a cord 242 that runs fromthe proximal body 246 of the curveable cannula 230, and terminates at anaperture 236 in the distal link 232. In some embodiments, the distal endof cord 242 terminates at a ball 238 that is disposed in a counter-bore,countersink, or like retaining surface of the aperture 236 to retain thecord within the distal link 232.

Referring now to FIG. 10B, once the trocar 210 is in place, stop nut 240is threaded proximally along external threads 248 of the proximal end246 of the curveable cannula 230 to allow motion of the cannula 230distally downward in recess 214.

The proximal body 246 of curveable cannula 230 may then be deployeddownward within trocar recess 216, as shown in section view in FIG. 13.As there may be resistance from the bony mass of the vertebral body (orother bony mass), the cannula 230 may be tapped downward by striking theproximal surface of cap 290 (e.g. with a mallet or the like) whileholding the trocar at housing 202. In several embodiments, the motion ofproximal body 246 pushes tube 244 distally within channel 218 of thetrocar body 204. This motion forces the leading edge 232 and trailingmating links 234 out of the radial window 212 in tube 204, as shown inFIG. 14. The distal end of opening or window 212 comprises a ramp 209 tofacilitate the leading edge 232 out the window 212 at the proper anglewith respect to the trocar tube 204 central axis, and without catchingor getting stuck at the distal end of the trocar 210.

In some embodiments, a pull cord 242 is coupled to the distal tip of thecurveable cannula 230, the pull cord extending to the proximal end ofthe trocar 210. In addition to the ramp 209, the curved path of thedistal tip 233 is facilitated by tension provided by cord 242, whichforces the mating links 232, 234 to arch upon the applied tension. Thepull cord may be configured to apply a tensile force to the distal endof the curveable cannula to bias the curveable cannula into a curvedconfiguration. In some embodiments, the cord 242 is coupled tomale-threaded dial 212 (see FIG. 8) to act as a pull cord to apply saidtension. The dial 212 may be turned clockwise or counterclockwise withininternal-threaded arm 214 to increase or relieve the tension on the cord242, thereby providing steering of the distal tip 233 while thecurveable cannula 230 is advanced down trocar body 204 and out window212 (e.g. increased tension provides a sharper radius, decreased tensionprovides a more relaxed or no radius.) The tensile force applied to thedistal tip of the curveable cannula 230 may be controlled from theproximal end of the trocar to steer the curveable cannula 230 along adesired path.

Alternatively, cord 242 may comprise a memory material such as a Nitinolwire that fastens the tube 244 and links 232, 234 in a preformedcurved-shape. The cord 246 in this configuration stretches to allow thecurveable cannula 230 to be delivered into and stowed in a linear formwithin channel 218, and retracts when not restrained in channel 218 todrive a curved path when exiting window 212.

As shown in FIGS. 13 and 14, the curveable cannula 230 is fullydeployed, with the proximal end 246 disposed at the bottom of recess216, and the distal tip 233 in a deployed orientation forming a curvedpath (along with trailing links 234) through the bone at the treatmentsite. In this configuration, the probe 250 is restrained from axialmotion (in the distal direction) with respect to the curved cannula 230,because it is threaded inside a threaded recess portion of drive nut270, which is restrained from distal motion by stop 258 in the proximalend 246.

As shown in FIG. 15, the drive nut 270 may be raised (proximallyadvanced out of cavity 268) with respect to the curveable cannula 230and probe proximal body 254 by rotating the drive nut 270. The proximalbody 254 of the probe 250 comprises a male thread 256 that mates withthe female internal threads 262 in a distal recess of the drive nut 270.The thread pattern 256/262 may be opposite of the thread pattern betweenthe stop nut 240 and proximal end 246 of the curveable cannula 230 (e.g.right-handed thread vs. left-handed thread), so that rotation of thedrive nut 270 does not result in rotation of the curveable cannula 230.

Furthermore, the proximal end 254 of the probe 250 comprises a pluralityof vertical grooves 264, at least one of which interfaces with key 266of the curveable cannula 230. This interface only allows axial motion ofthe proximal body 264 with the curveable cannula 230, and restrictsrotation of the proximal body 264 with the curveable cannula 230. Thus,rotation of the drive nut 270 may only result in proximal translation ofthe drive nut 270. As seen in FIG. 15, the probe proximal body 254 isnow free to move downward in cavity 268.

Referring now to FIGS. 16 and 17, the system 201 is shown in a fullydeployed state, with the distal shaft of the probe 250 advanced beyonddistal end 233 of the curveable cannula central channel 245. In severalembodiments, this deployment is achieved by advancing the proximal body254 within the cavity 268 of the curveable cannula 230. In severalembodiments, the proximal body 254 and drive nut 270 are advanced as aunit within cavity 268 (e.g., by tapping the cap 290), thereby providingan impact force to advance the probe tip 274 out of the cannula 230 andthrough tissue and/or bone to reach the desired treatment or diagnosticlocation within the body.

In one embodiment, a channeling stylet (such as stylet 90 shown in kit10 of FIG. 1) may also be used to create a working channel beyond theend of the curved path created by the curveable cannula 230 prior todeploying a probe for treatment or diagnostic purposes.

Once the distal tip 274 of the probe 250 is positioned at the desiredlocation, treatment of the target tissue may be performed. As shown inFIG. 17, probe distal end 274 may comprise a first electrode 274configured to deliver a therapeutic amount of RF energy to the targetlocation. In the configuration shown in FIG. 17, the probe 250 comprisesa bipolar probe with a return electrode 276, however, in variousembodiments, the probe 250 comprises any treatment instrument or devicedescribed herein.

Cap 290 may further be configured to include (e.g. a self containedunit) a power source (e.g. battery) and receptacles (not shown) tocouple to the probe 250, thereby supplying the energy to deliver atherapeutic level of energy to the tissue. In this configuration, thecap 290 may have sufficient power to deliver one or more metered dosesof energy specifically measured to modulate (e.g., denervate) at least aportion of the BVN of a vertebral body.

The cap 290 may be threaded (or otherwise releasable coupled) into drivenut 270 to be interchangeable depending on the application or step ofthe procedure. For example, a cap 290 having a reinforced/hardenedsurface 292 used for driving the system 201 into the bone may bereplaced by another cap having couplings (not shown) for probe 250, aninternal power supply (not shown), or couplings for an external powersupply/controller (not shown) for delivering energy for treatment and/ordiagnosis of a region of tissue. For embodiments wherein a fluid and/oragent is delivered to the target tissue, the cap 290 may be configuredto facilitate delivery of the fluid through a probe having one or morefluid delivery channels. In some embodiments, the interchangeable cap290 is configured to provide access to the probe 250 for providing atherapeutic energy.

FIGS. 18A and 18B are side views of the distal end of the system 201with the curveable cannula 230 in a stowed and deployed positionrespectively. The distal link 232 and trailing links 234 are configuredto have mating/interlocking surfaces that allow the distal end of thecannula to curve in one direction. The more distal link of a mating pairwill have an extension 235 that mates with a correspond depression 237in the link proximal to it. This allows the links to rotate with respectto each other to create a curved distal end as shown in FIG. 18B.

FIGS. 19A and 19B illustrate an alternative system 300 for generating acurved channel through bone. System 300 comprises a tubular trocar body302, the proximal end (not shown) of which may comprise a portion or allof any of the previously described proximal ends for devices 10,200, or201 disclosed herein. The distal tip 334 comprises a leading edgesurface for advancing through bone, and a radial or lateral window 304allowing access to the central channel of the trocar body 302. Thewindow 304 is positioned a short distance proximal to the distal tip334.

A curveable cannula 322 is positioned in the trocar 302, the curveablecannula 322 having a distal end 324 coupled via linkage 326 to apivotable arm 310. The proximal end (not shown) of the curveable cannulamay comprise a portion or all of any of the previously describedproximal ends for devices 10, 200, or 201 disclosed herein. Thepivotable arm 310 has a first end pivotably coupled at joint 314 at alocation at or near the distal tip 334 of the trocar 334. In a stowedconfiguration (illustrated in FIG. 19A), the pivotable arm is configuredto lay axially in the trocar 302 within slot 306 that runs from pivot314 proximally to the radial opening or window 304. The proximal (whenstowed) end 312 of the arm 310 is coupled to the linkage 326.

As shown in FIG. 19B, the cannula 322 may be advanced laterally outwardfrom window 304 by simply advancing the cannula 322 distally down thetrocar 302. The pivotable arm 310 constrains the motion of the curveableend 320 of the cannula to a curved path of specified radius (determinedby the length of arm 310. Once the pivotable arm has reached fullrotation (shown approximately 90 degrees in FIG. 19B, however such anglemay be specified to be any desired amount), the cannula end 320 hascreated a curved path outward from the trocar toward the desiredtreatment site. A probe, stylet or similar device (such as curved stylet60, channeling stylet 90, or probe 100 of FIG. 1) may be positioned atthe opening of the distal end 320 to facilitate generating the curvedbore without allowing tissue or bone to enter the cannula. The probe ortreatment and/or diagnostic device may then be routed through thecannula end 320 to a region of tissue or bone that is off-axis from thetrocar body 302.

According to several embodiments, the above systems 201, 300 may beprovided as a kit of instruments to treat different regions of the body.For example, the location, orientation and angle of the treatment devicewith respect to the trocar may be varied by providing a set ofinstruments at varying increments. This may be achieved by varying thecurvature in the curveable cannula (230, 320). The curvature may bevaried by varying the radius of curvature, the insertion depth (shaftlength and tip length, and/or the final exit angle with respect to thetrocar central bore. Thus, the physician may select a different kit fortreating a lumber spine segment as opposed to a sacral or cervical spinesegment, as the anatomy will dictate the path that needs to bechanneled.

According to several embodiments, each of the instruments in the systems10, 200, 201, and 300 detailed above may have any length, shape, ordiameter desired or required to provide access to the treatment and/ordiagnostic region (e.g. intraosseous nerve or basivertebral nerve trunk)thereby facilitating effective treatment/diagnostic of the targetregion. For example, the size of the intraosseous nerve to be treated,the size of the passageway in the bone (e.g. pedicle 138) for accessingthe intraosseous nerve, and the location of the bone, and thus theintraosseous nerve, are factors that that may assist in determining thedesired size and shape of the individual instruments. In severalembodiments, the treatment device (e.g., RF probe) has a diameterbetween 1 mm and 5 mm (e.g., between 1 mm and 3 mm, between 2 mm and 4mm, between 3 mm and 5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or any diameterbetween the recited ranges).

The systems 10, 200, 201 and 300 described above may be used with anumber of different treatment modalities for therapeutic treatment ofthe target region, which may be spinal or non-spinal. For example, inone embodiment, it is desirable to operate the treatment devices orprobes in systems 100, 200, 201 and 300 in a manner that denervates(e.g., ablates) the tissue of the target region (e.g. BVN) to produceheat as described in U.S. Pat. No. 6,699,242, herein incorporated byreference in its entirety.

In another embodiment, the treatment device is configured to delivertherapeutic treatment that is targeted to block nerve conduction withoutablating the nerve. For example, thermal treatment (e.g., a thermalenergy dose) can be delivered to the nerve (e.g. via thermal therapy,agent or the like) that results in denervation of the BVN withoutnecrosis of tissue. This non-ablative treatment may be achieved viadelivery of a lesser amount of energy or agent to the tissue site(either in the form of less exposure time, concentration, intensity,thermal dose, etc.) than is required for ablation, but an amountsufficient to achieve some amount of temporary or permanent denervation.

In accordance with several embodiments, the treatment devices (e.g.,probes) described herein may comprise non-therapy devices or elements,such as diagnostic devices (e.g. ultrasound, cameras, sensors, or thelike) to diagnose a region of tissue independent of or in connectionwith treatment of the region of tissue.

In several embodiments, individual elements of any of the systems 10,200, 201, and 300 detailed above may be used interchangeably whereapplicable. For example, the curved stylet 60 shown in systems 10 and200 may be temporarily implemented in place of the probe of systems 201and 300 to provide additional curving bias to the curveable cannula(230, 320) while the cannula is being driven into the bone. Furthermore,the channeling stylet 90 may be used to further generate a channelbeyond the curved path provided by the curveable cannula (230, 320).

FIGS. 25-51 illustrate additional embodiments of systems, devices andmethods for modulation of nerves (e.g., intraosseous nerves orbasivertebral nerves) within bone (e.g., vertebral bodies of the spine),as well as features, elements, structures, and method steps that may beincorporated into the embodiments described above.

As used herein, the “resistive heating zone,” in addition to itsordinary meaning, is the zone of bone tissue that is resistively heateddue to an energy loss incurred by current travelling directly throughthe bone tissue. Resistive heating, “joule” heating and “near-field”heating may be used interchangeably herein. The “conductive heatingzone,” in addition to its ordinary meaning, is the zone of bone tissuethat is heated due to the conduction of heat from an adjacent resistiveheating zone. The total heating zone (THZ) in a bone tissue includesboth the resistive heating zone and the conductive heating zone. Theborder between the conductive and resistive heating zones is defined bythe locations where the strength of the electric field is 10% of themaximum strength of the electric field between the electrodes. As usedherein, the heating zones encompass the volume of bone tissue heated toat least 42° C. by embodiments described herein. As used herein, the“first and second sides” of a vertebral body are the lateral-lateralsides intersected by the BVN. The modulation of the ION may be carriedout by resistive heating, conductive heating, or by hybrid heating.

In some embodiments, the therapeutic heating of the ION is provided byboth resistive and conductive heating. In some embodiments thereof, asin FIG. 25, the electrodes are placed such that the ION passes throughresistive heating zone IR, so that length L₂ of the ION istherapeutically heated by bone tissue in the resistive heating zone IRand lengths L₂ and L₃ of the ION are therapeutically heated by the bonetissue in the conductive heating zone OC.

In embodiments wherein the therapeutic heating of the ION is providedsubstantially by both resistive and conductive heating, it may bepreferred that the length L₁ of the ION treated by resistive heatingcomprise at least 25% or at least 50% of the total therapeuticallytreated length of ION. In other embodiments, the length may be in therange of 10-25% of the treated length of ION, in the range of 40-60% ofthe treated length of ION, in the range of 50-70% of ION, greater than70% of the treated length of ION, or overlapping ranges thereof. Inseveral embodiments, the peak temperature in the resistive heating zoneIR is between 40° C. and 60° C. greater than the peak temperature in theconductive heating zone OC. In some embodiments, the peak temperature inthe resistive heating zone IR is between about 20° C. and 40° C. greaterthan the peak temperature in the conductive heating zone, between about10° C. and 20° C. greater than the peak temperature in the conductiveheating zone OC, between about 5° C. and 10° C. greater than the peaktemperature in the conductive heating zone OC, between 0° C. and 5° C.greater than the peak temperature in the conductive heating zone OC inthe range of 2° C. and 5° C. greater than the temperature in theconductive heating zone OC, or overlapping ranges thereof. In someembodiments, the peak temperature in the resistive heating zone IR is nomore than 15° C. greater than the peak temperature in the conductiveheating zone OC, no more than 10° C. greater than the peak temperaturein the conductive heating zone OC, or no more than 5° C. greater thanthe peak temperature in the conductive heating zone OC.

Now referring to FIGS. 29A and 29B, in some embodiments, the therapeuticheating of the ION is provided essentially by the conductive heatingzone OC. This may occur when the ION is in fact located substantiallyfar from the middle of the ION residence zone IRZ. In such an instance,the electrodes are placed such that the ION passes only through theconductive heating zone, so that length L₂ of the ION is therapeuticallyheated by bone tissue in the conductive heating zone OC.

In some embodiments thereof, it may be desired that the separationdistance (SD) between the ION and the resistive heating zone IR be nomore than 1 cm. This is desired because the closer the ION is to theresistive heating zone, the higher the temperature experienced by theION length L₂. In some embodiments, the separation distance is no morethan 0.5 cm or no more than 0.2 cm. In some embodiments, the SD isbetween 1 cm and 2 cm, between 0.75 and 1 cm, between 0.5 and 0.75 cm,between 0.3 cm and 0.6 cm, between 0.1 cm and 0.3 cm, between 0.02 cm toabout 0.2 cm, or overlapping ranges thereof.

In some embodiments, as in FIGS. 29A and 29B, the electric field issufficiently strong to be located substantially continuously between thetwo electrodes. This typically occurs when the electrodes are very closetogether (i.e., no more than 5 mm, no more than 4 mm, no more than 3 mm,no more than 2 mm apart). In other embodiments, however, as in FIG. 30,the electric field is relatively weak and so resides substantially onlyin the vicinity of the two electrodes. In such cases, and now referringto FIG. 30, inward energy flow from the resistive heating zone IRconductively heats the intermediate area of the conductive heating zoneOCI. In several embodiments, the peak temperature in the resistiveheating zone IR is no more than 15° C. greater than the peak temperaturein the intermediate conductive heating zone OCI, no more than 10° C.greater than the peak temperature in the intermediate conductive heatingzone OCI, or no more than 5° C. greater than the peak temperature in theintermediate conductive heating zone OCI.

In several embodiments, methods are carried out via a dual probe system.In particular, embodiments of the dual probe system comprise an energydelivery device comprising a first probe having an active electrode anda second probe having a return electrode. Now referring to FIG. 31, thisdual probe embodiment can allow the surgeon to approach the BVN fromseparate sides of the vertebral body to easily straddle the IRZ with theelectrodes. With such a device, the surgeon can place the first probe601 having an active electrode 603 on a first side of the vertebral bodyand the second probe 611 having a return electrode 613 on a second sideof the vertebral body, and then align the paired electrodes so thattheir activation produces a total heating zone that straddles the IRZ,and therefore the BVN therein.

In several embodiments, aligning the electrodes of such an apparatus tostraddle the ION merely requires advancing the probes into the vertebralbody and no complicated navigation is required. According to severalembodiments, even if the location of the BVN were precisely known,conventional methods of accessing the BVN require either the BVN to benaturally located within the vertebral body so as to intersect the axisof the pedicle, or require a complicated probe configuration ornavigation. In some embodiments, a dual probe approach simply requiressubstantially linear advance of a pair of substantially straight probes,and is much simpler and/or much more robust than the conventionalmethods of accessing nerves in bone. For example, the clinician maydesirably access the vertebral body through the pedicles withsubstantially straight probes and have a high confidence that theiractivation can therapeutically treat the BVN.

In accordance with embodiments of the invention, there is provided amethod of therapeutically treating a vertebral body having a BVN,comprising providing an energy device having an active electrode havinga first face and a return electrode having a second face into thevertebral body, and placing the active electrode in the vertebral bodyto face a first direction. The return electrode can then be placed inthe vertebral body to face a second direction, with the first and secondfaces defining an angle 2

of no more than 60 degrees. A sufficiently high frequency voltagedifference can then be applied between the active and return electrodesto generate a current therebetween to produce a total heating zone totherapeutically heat (e.g., denervate or ablate) the BVN.

In accordance with embodiments of the invention, there is provided amethod of therapeutically treating a vertebral body having a BVNcomprising: providing an energy device having an active electrode and areturn electrode, placing the active and return electrodes in thevertebral body to define an electrode axis, the axis forming an angle Cof between 50 and 90 degrees with the BVN, and applying a sufficientlyhigh frequency voltage difference between the active and returnelectrodes to generate a current therebetween to produce a total heatingzone to therapeutically heat (e.g., denervate or ablate) the BVN.

Now referring to FIG. 32, there is provided a dual probe apparatuscomprising first 101 and second 151 cannulae, first 221 and second 251stylets, first 301 and second 351 probes, and a power supply 401 inelectrical connection with the probes. For simplicity, only a singlecannula, stylet and probe will be further described. However, manyembodiments use two sets of such devices.

Now referring to FIG. 32, cannula 101 comprises a shaft 103 having alongitudinal bore 105 therethrough defining an inner diameter D_(C).Distal opening 109 of the cannula provides a working portal for theprobe. It is further sized to allow the distal end of the probe toadvance past the distal end 107 of the cannula. The length L_(C) of thecannula is sized to reach from the patient's skin to a location withinthe cancellous bone region of the target bone. In several embodiments,the cannula comprises metal and/or polymer (e.g., Nitinol or polyetherether ketone (PEEK). In many embodiments, the cannula is made of aninsulating material in order to prevent stray current from the probefrom contacting non-targeted tissue.

In some embodiments, the cannula is shaped so as to guide the probetowards the midline of the vertebral body. This inward guidance willhelp move the electrodes closer to the BVN. In some embodiments, atleast a portion of the cannula bore is curved. In some embodiments, atleast half of the length of the cannula bore is curved. In otherembodiments, substantially only the distal end portion of the cannulabore is curved.

Stylet 221 comprises a shaft 203 having a longitudinal axis F and aproximal 205 and distal end 207. Disposed at the distal end of the shaftis a tip 219 adapted for boring or drilling through cortical bone. Insome embodiments, the outer diameter D_(O) of the stylet shaft ispreferably adapted to be received within the inner diameter D_(C) of thecannula.

The combination of the cannula and the stylet is sometimes referred toherein as a “cannulated needle.” In some embodiments, access to thevertebral body is gained by first placing the stylet in the cannula toproduce a cannulated needle, piercing the skin with the cannulatedneedle, and advancing the cannulated needle so that the stylet tipreaches a target tissue region within the cancellous portion of thevertebral body, and then withdrawing the stylet. At this point, thecannula is conveniently located at the target tissue region to receive aprobe.

Probe 301 comprises a shaft 303 having a longitudinal axis G, a distalend portion 305 and a proximal end portion 307. Disposed near the distalend portion of the probe is a first electrode 309 having a first face331 and a connection face 333. The probe 301 is designed so that theconnection face 333 of the first electrode is placed in electricalconnection with a first lead 403 of the power supply. In this particularembodiment, the shaft has a longitudinal bore 311 extending from theproximal end portion up to at-least the first electrode 309. Disposedwithin the bore is a wire 321 electrically connected at its first end323 to the first electrode 309 and having a second end 325 adapted to beelectrically connected to a first lead of a power supply.

Several embodiments of systems comprise a cannula having a longitudinalbore, a stylet having an outer diameter adapted to be received withinthe longitudinal bore, and a distal tip adapted to penetrate corticalbone. The systems may comprise a probe or other treatment device. In oneembodiment, the probe includes an outer diameter adapted to be receivedwithin the longitudinal bore, a first electrode, and a lead inelectrical connection with the first electrode. A second, third, orfourth electrode is provided in some embodiments. In severalembodiments, second, third, or fourth probes are provided.

In some embodiments, the outer surface of the probe or other treatmentdevice is provided with depth markings or other indicia so that theclinician can understand the extent to which it has penetrated thevertebral body.

In some embodiments in which a cannulated stylet is first inserted, thestylet is removed and the cannula remains in place with its distalopening residing in the target tissue while the probe is inserted intothe cannula. In one embodiment, the cannula provides a secure portal forthe probe, thereby ensuring that the probe can enter the bone safely.This embodiment may be particularly advantageous when the probe is madeof a flexible material, is curved, or is shaped with an irregularcross-section that could undesirably catch on the bone during probeadvancement into the bone.

In the FIG. 32 probe disclosed above, probe 301 has a blunt tip. Inother embodiments; however, the probe carrying at least one electrodecan be configured to possess a sharp distal tip having sufficientsharpness to penetrate cortical bone. With such a tip, the clinician caneliminate steps in the procedure that are related to either the styletor the cannulated stylet, and thereby save time.

Now referring to FIG. 33, in some embodiments, the electrode may includea portion of the probe shaft. For example, in the case of probe 1401,the probe comprises: an inner electrically conductive shaft 1403 inelectrical connection with a power supply 1409, and an outer insulatingjacket 1405 wrapped around a portion of the shaft.

In this configuration, the placement of the jacket provides a distaluninsulated shaft portion 1407 that could be used as an electrode. Inseveral embodiments, the distal uninsulated portion of the shaft has alength of between 3 mm and 8 mm (e.g., about 5 mm) In some embodimentsthereof, the insulation is selected from the group consisting ofpolyimide tape, PTFE tape, and heat shrink tubing. Preferred thicknessof the insulation may range from about 0.00025 to 0.0005 inches.

In some embodiments using insulating jackets, the jacket has either alongitudinally extending slit or slot that exposes a longitudinalsurface area of the underlying shaft, thereby producing either anessentially linear or an essentially planar electrode. In suchembodiments, the distal end of the shaft is insulated. In otherembodiments using insulating jackets, the insulated portion may comprisea proximal jacket and a distal jacket positioned to provide a spacetherebetween that exposes a surface area of the underlying shaft toproduce the electrode. In some embodiments, the proximal and distaljackets substantially encircle the shaft to provide an annular electrodetherebetween.

In some embodiments in which a cannulated stylet is used, both thestylet and the cannula are removed, and the probe is inserted into thehole created by the cannulated stylet. In one embodiment, the holeprovides a large portal for the probe. This embodiment conserves theannulus of bone removed by the cannula, and so may be preferred when theprobe has a relatively large diameter (e.g., more than 8 mm indiameter). In some embodiments, the cannula remains to ensure that theprobe tracks the hole and does not form its own pathway through thecancellous bone.

In some embodiments in which a cannulated stylet is used, the cannulacomprises at least one electrode. In one embodiment, the cannula acts asthe probe as well. With this embodiment, the clinician can eliminatesteps in the procedure that are related to introducing a body into thecannula. In some embodiments, the outer surface of the cannula isprovided with depth markings so that the clinician can understand theextent to which the cannula has penetrated the vertebral body.

In some embodiments in which a cannulated stylet is first inserted, thestylet comprises at least one electrode. In this embodiment, the styletacts as the probe as well. With this embodiment, the clinician caneliminate steps in the procedure that are related to removing the styletand introducing a body into the cannula. In some embodiments, the outersurface of the stylet is provided with depth markings so that theclinician can understand the extent to which it has penetrated thevertebral body.

In conducting initial animal experiments with a dual probe embodiment, abipedicle approach was used as shown in FIG. 31, so that each probeapproached the ION at angle

of 45 to about 55 degrees. Since both the probes and the electrodesdisposed thereon were essentially cylindrical, the inner faces 605, 615of the electrodes produced an angle 2

. Subsequent testing of the configuration of FIG. 31 revealed somewhathigher temperatures at the distal portion of the electrodes and somewhatlower temperatures near the proximal portions of the electrodes. Withoutwishing to be bound by a particular theory, it is believed that theshorter path between the distal regions produced a lower resistanceregion (as compared to more proximal interelectrode regions) and socaused current to preferentially follow the path of the least resistancebetween the distal portions. Accordingly, the present inventors soughtto improve upon the relatively uneven temperature profile produced bythe electrode design of FIG. 31.

In accordance with embodiments of the invention, the electrode designcan be modified to reduce the angle 2

produced by the inner faces, so that the distance between the proximalend of the electrodes is more equal to the distance between the proximalend of the electrodes (e.g., the faces are more parallel). When theelectrodes are provided in such a condition, their orientation reducesthe significance of any path of least resistance, and so current flowsmore evenly across the face of each electrode, thereby providing evenheating and greater control over the system.

In accordance with embodiments of the invention, there is provided anintraosseous nerve modulation system. In one embodiment, the modulationsystem comprises a first probe having an active electrode and a firstlead, a second probe having a return electrode and a second lead, meansfor creating first and second bores within a bone for accommodating thefirst and second probes, and a power supply capable of generating avoltage difference between the active and return electrodes. In oneembodiment, the power supply comprises third and fourth leads, whereinthe first and third leads are in electrical connection, and the secondand fourth leads are in electrical connection.

In some embodiments the electrodes are disposed so that the angle 2

produced by the inner faces is less than 60 degrees (e.g., no more than30 degrees). In other embodiments, the angle is less than 1 degree. Insome embodiments, the inner faces are substantially parallel.

Now referring to FIG. 34, in some embodiments, substantially parallelelectrodes are provided by using conical electrodes 501 that taperdistally. In FIG. 34, each cone electrode 501 has a distal end 503having a diameter D_(D) and a proximal end 505 having a diameter D_(P),wherein the distal end diameter D_(D) is larger than the proximal enddiameter D_(P). In several embodiments, the angle γ of the cone taper issubstantially equal to the angle δ. In this condition, the inner facesof the conical electrodes will be essentially parallel to each other.

In accordance with embodiments of the invention, there is provided anintraosseous nerve denervation system comprising a first probe having afirst electrode and a first lead in electrical connection with the firstelectrode, wherein the first electrode has a proximal end having aproximal diameter and a distal end having a distal diameter, and theproximal end diameter is less than the distal end diameter, and,optionally a second probe. In one embodiment, the second probe comprisesa first electrode and a first lead in electrical connection with thefirst electrode. In one embodiment, the first electrode has a proximalend having a proximal diameter and a distal end having a distaldiameter, wherein the proximal end diameter is less than the distal enddiameter. In one embodiment, the first and second electrodes aredisposed so that the electrodes are parallel. Non-parallel positioningis provided in other embodiments.

In FIG. 35, the conical shapes are frustoconical (i.e., they areportions of a cone). Frustoconical electrodes are desirable insituations where tissue charring needs to be avoided, as the relativelylarge diameter of the distal end of the electrode can not provide anavenue for high current density (relative to the proximal end of theelectrode). Frustoconical electrodes are also desirable in situationswhere the probes are disposed at a relatively high angle γ, wherein theuse of sharp tipped electrodes would substantially shorten the distancebetween the distal tips of the electrodes and thereby create anundesirable path of significantly less resistance.

In some embodiments, the frustoconical electrode is shaped so that thediameter of its distal end D_(D) is between about 10% and 25% of thediameter of its proximal end D_(P). In some embodiments, thefrustoconical nature of the electrode is provided by physically severingthe sharp distal end of the electrode. In others, the frustoconicalnature of the electrode is provided by insulating the sharp distal endof an electrode.

As noted above, when the probes are placed such that their correspondingelectrodes are parallel to each other, the electric field produced byelectrode activation is substantially uniform between the distal andproximal portions of the electrodes. However, as the probes are orientedat an angle from parallel, the electric field becomes strongest wherethe electrodes are closer together. In order to compensate for thisnonuniform electric field, in some embodiments, the distal ends of theelectrodes are tapered. In this tapered state, the regions of theelectrodes that are closer together (e.g., the tip) also have a smallersurface area (thereby reducing the electric field in that region), whilethe regions of the electrodes that are farther apart (e.g., the trunk)have a larger surface area (thereby increasing the electric field inthat region). Typically, the effect is largely determined by the conesize, electrode spacing and tissue type therebetween.

In some embodiments of the tapered electrode, and now referring to FIG.35, the distal end of the electrode terminates in a sharp tip, so thatthe electrode has a more completely conical shape. In severalembodiments, the conical electrode is shaped so that the diameter of itsdistal end is no more than 20%, no more than 10%, or no more than 1% ofthe diameter of its proximal end. In addition to compensating fornon-uniformity in the electric field, the sharp tip may also be adaptedto penetrate the outer cortical shell of the vertebral body.

Now referring to FIG. 36, in some embodiments, current flows through anelectrode having only a portion of the conical or frustoconical shape.When electrodes of this embodiment, termed “sectored cones,” face eachother, their use is advantageous because they ensure that current flowsthe least distance, and so provide efficiency. The sectored cones ofthis embodiment can be produced by first manufacturing planar electrodes511 and placing the planar electrode upon a conveniently angled probesurface 513. Alternatively, this embodiment can be produced by firstmanufacturing the conical electrode configuration of FIG. 36, and thenmasking a portion of the conical electrode with an insulating material.Unlike the embodiment of FIG. 36, this sectored cone embodiment requirescareful alignment of the electrode faces and may require in vivorotation of the electrodes to achieve the desired alignment.

Now referring to FIG. 37, in other embodiments, substantially parallelelectrodes can be provided by using elbowed probes 531. The elbowedprobes can have a distal end 533 and a proximal end 535 meeting at anelbow 537. In some embodiments, the elbow may be produced during themanufacturing process (thereby requiring a smaller diameter probe inorder to fit through the cannula). In other embodiments, the elbow isproduced in vivo, such as through use of a pull-wire, a pivot or amemory metal disposed within the probe.

Now referring to FIG. 38, in some embodiments, first 551 and. second 552cannulae are each provided with a curved bore 553, 554 forming distallateral openings 563, 564 in their respective distal end portions 555,556. When flexible probes 557, 558 containing an electrode 559, 560 arepassed through the curved bore, the distal end 561, 562 of the probelikewise conforms to the curved bore, thereby forming an intraprobeangle E determined by the proximal A_(P) and distal A_(D) axes of theprobe. In several embodiments, this intra-probe angle is between 90 and135 degrees, between 90 and 105 degrees, between 100 and 120 degrees,between 115 and 135 degrees, between 70 and 100 degrees, between 120 and160 degrees, or overlapping ranges thereof. In several embodiments, theintra-probe angle is selected so that the distal axes A_(D) of theprobes exiting the cannulae form an angle of no more than 30 degrees, nomore than 10 degrees, or form a substantially parallel relation. In someembodiments, the distal axes of the probes form an angle between 20-50degrees, between 15-30 degrees between 5-15 degrees, between 0-8degrees, or overlapping ranges thereof.

In accordance with embodiments of the invention, there is provided anintraosseous nerve denervation system, comprising a cannula having alongitudinal bore defining a first axis, a stylet having an outerdiameter adapted to be received within the longitudinal bore and adistal tip adapted to penetrate cortical bone, and a first probe. In oneembodiment, the first probe comprises an outer diameter adapted- to bereceived within the longitudinal bore, a first electrode, and a lead inelectrical connection with the first electrode. Additional probes and/orelectrodes are provided in other embodiments.

Now referring to FIGS. 39A and 39B, in some embodiments, first 701 andsecond 751 cannulae are each provided with a curved bore 703, 753 intheir respective distal portions 705, 755, wherein each bore has aproximal lateral opening 707, 757. The apparatus further comprises firstand second probes 711, 761, each containing an electrode 713, 763. Insome embodiments, the probe may sit in a distal region of the bore (asin FIG. 39A) during advance of the cannula. Once the target tissueregion is reached, then probes are moved proximally (by, for example, apull wire—not shown) and exit the proximal lateral openings so that theinner faces 715, 765 of the electrodes face other.

Therefore, there is provided an intraosseous nerve denervation system,comprising a cannula having a longitudinal bore defining a first axis, astylet having an outer diameter adapted to be received within thelongitudinal bore and a distal tip adapted to penetrate cortical bone,and probe or other treatment device. In one embodiment, the probe orother treatment device comprises an outer diameter adapted to bereceived within the longitudinal bore, at least one electrode, and alead in electrical connection with the at least one electrode. Multipleprobes and multiple electrodes may be provided in some embodiments.

Now referring to FIGS. 40A and 40B, in some embodiments, at least oneprobe 801 comprises a distal portion 803 having an electrode 805 and aproximal portion 807, with the distal portion being pivotally attachedto the proximal portion by pivot 809. In some embodiments, two probeshaving such pivotally attached electrodes are introduced through thecannulae in a first linear mode (shown in FIG. 40A) to produce an angleZ between the electrodes. Next, the respective pivots may be actuated(by for example, a pull wire—not shown) to produce the angledconfiguration shown in FIG. 40B which reduces the angle between theelectrodes. In accordance with several embodiments, the pivoting bringsthe electrodes into a substantially parallel relation.

In some embodiments, relatively even heating is provided by providingcurrent density gradients. Now referring to FIG. 41, in someembodiments, first 821 and second 831 probes have first 823 and second833 electrodes having a reverse conical shape. One or more electrodescan have a proximal end having a proximal diameter and a distal endhaving a distal diameter, with the proximal end diameter being less thanthe distal end diameter. In particular, each electrode may have arelatively thick distal portion 827, 837 and a relatively thin proximalportion 825, 835. When this probe is activated, it is believed that thecurrent density of the electrodes will vary axially, with a relativelyhigh current density present at the proximal portion of each electrode(due to the smaller surface area) and a relatively low current densitypresent at the distal portion of the electrode (due to the largersurface area). This current density gradient may advantageously providea more even heating zone when the electrodes themselves are oriented ata significant angle, as the preference for tip heating (caused by theangled orientation of the electrodes) is substantially balanced by thehigher current density at the proximal portions of the electrodes.

Current density gradients can also be produced by providing a pluralityof electrodes on each probe. Now referring to FIG. 42, in someembodiments, first and second electrodes each have a plurality ofelectrodes. In particular, first probe 851 has first 853, second 854 andthird 855 active electrodes, while second probe 861 has first 863,second 864 and third 865 return electrodes. The voltage across theprobes can be selected so that there is increasing voltage (andtherefore current) across the more widely spaced electrodes (e.g.,V₈₅₅₋₈₆₅<V₈₅₄₋₈₆₄<V₈₅₃₄₆₃). In some embodiments, the probes of FIG. 42are driven by multiple voltage sources (i.e., a first voltage source forproviding voltage between first active electrode 853 and first returnelectrode 863, etc.).

In accordance with several embodiments, a method of therapeuticallytreating a vertebral body having a BVN comprises providing a firstenergy device having distal and proximal active electrodes, providing asecond energy device having distal and proximal return electrodes,placing the first and second energy devices in the vertebral body todefine a first distance between the distal active electrode and thedistal return electrode, and a second distance between the proximalactive electrode and the proximal return electrode. In one embodiment,the first distance is less than the second distance. In one embodiment,the method further comprises applying a first high frequency voltagebetween the distal active and distal return electrodes, and applying asecond high frequency voltage between the proximal active and proximalreturn electrodes, with the first high frequency voltage being less thanthe second high frequency voltage.

Because multiple voltage sources may add complexity to the device, inother embodiments, the differences in voltage may be provided by asingle voltage source by using a poorly conductive electrode. Inparticular, in some embodiments thereof, the probe comprises anelectrically conductive probe shaft and a plurality of spaced apartinsulating jackets, wherein the spacing produces the electrodes of FIG.42. In this jacketed embodiment, the probe shaft can be made of amaterial that is a relatively poor electrical conductor (such astantalum) so that, when a single driving force, is applied between thejacketed probes, the voltage is highest at the proximal electrode 853,but loss due to the poor conductance produces a substantially lowervoltage at distal electrode 855. This jacketed embodiment mayadvantageously eliminate the need for multiple voltage sources.

In another dual probe approach, in some embodiments, and now referringto FIG. 43, there is provided an apparatus having first probe 871 havingan active electrode 873, and a second 881 probe having a returnelectrode 883, wherein the ratio of the surface area of the activeelectrode to the surface area of the return electrode is very high, suchas at least 2:1 (e.g., at least 5:1). In this condition, the currentdensity can be very high at the active electrode and very low at thereturn electrode, so that the total heating zone THZ can occuressentially only around the active electrode. Since this device heatsessentially only at the active electrode, this device substantiallymimics, the heating profile of a monopolar electrode, but provides thedesirable safety feature of locally directing the current to the returnelectrode.

Although the dual probe approach has many benefits in some embodiments,a single articulated probe having both active and return electrodes maybe used in other embodiments. For example, a single probe may be placedsuch that a first electrode is on one side of midline (e.g., the leftside) and a second electrode is on the other side of midline (e.g., theright side) of the vertebral body, or vice-versa. In some embodiments,the probe is curved such that one electrode is at or near the tip of theprobe while the second electrode is near the beginning point of thecurved region of the probe. The curved probe may be placed such that oneelectrode is opposite the other and both occupy similar positionsrelative to the anterior and posterior limits of the vertebral body.This can advantageously allow placement such that the two electrodeseffectively straddle the BVN instead of using two separate probes. Insome embodiments, the active electrode is at or near the tip of theprobe, while in other embodiments, the return electrode is at or nearthe tip of the probe. In some embodiments, the first electrode comprisesa tip electrode and the second electrode comprises a ring electrode.

Now referring to FIG. 44, there is provided a articulated device. Insome embodiments, this device 900 comprises a fixed probe 901 and apivotable probe 951. Fixed probe 901 comprises a shaft 903 having alongitudinal axis and a distal end portion 905 comprising sharpeneddistal tip 906 and a proximal end portion 907. Disposed near the distalend portion of the probe is first electrode 909. The fixed probe may bedesigned so that the first electrode is placed in electrical connectionwith a first lead of a power supply. In this particular embodiment, theshaft has a longitudinal bore 911 running from the proximal end portionup to at least the first electrode disposed within the bore is a firstwire (not shown) electrically connected at its first end to the firstelectrode 909 and having a second end adapted to be electricallyconnected to a first lead of a power supply (not shown). The fixed probe901 also comprises a recess 927 forming a lateral opening in the shaftand designed to house the pivotable probe 951 when in its undeployedmode.

Pivotable probe 951 comprises a shaft 953 having a longitudinal axis, adistal end portion 955, and a proximal end portion 957 pivotallyattached to the fixed probe 901 by pivot 961. The pivot allows thepivoting probe 951 to pivot about the fixed probe 901. Disposed near thedistal end portion of the pivotable probe 951 is second electrode 963.The probe is designed so that the second electrode 963 is placed inelectrical connection with a second lead of the power supply.

In several embodiments, the pivotable probe has an undeployed mode and adeployed mode. In the undeployed mode, the pivotable probe is seatedwithin the recess of the fixed probe so that the axis of its shaft isessentially in line with the axis of the fixed probe shaft. In thisstate, the pivotable probe essentially hides within the fixed probe. Inthe deployed mode, the pivotable probe extends at a significant anglefrom the fixed probe so that the axis of its shaft forms an angle of atleast 10 degrees with the axis of the fixed probe shaft.

In some embodiments, a pusher rod is used to deploy the pivotable probe.Pusher rod 975 comprises a proximal handle (not shown) for gripping anda distal end portion 977 having a shape for accessing the bore of thefixed probe. Distal end portion has a tip 981 having a shape which, whenadvanced distally, can push the distal end portion of the pivotableprobe laterally out of the recess.

In several embodiments, the pivotable device has both an active and areturn electrode, and the device is introduced through a single pedicle.The location of these electrodes may vary depending upon the use of thepivotable device. For example, when the active electrode is located onthe pivotable probe, the return electrode may be positioned in alocation on the fixed probe distal of the pivot (as in FIG. 25), alocation on the fixed probe proximal of the pivot; a location on thepivotable probe located nearer the pivot, a location on the pusher rod,or other locations. In other embodiments, the locations of the activeand return electrodes are reversed from those described above.

In general, it may be desirable to operate embodiments of the inventionin a manner that produce a peak temperature in the target tissue ofbetween about 80° C. and 95° C. When the peak temperature is below 80°C., the off-peak temperatures may quickly fall below about 45° C. Whenthe peak temperature is above about 95° C., the bone tissue exposed tothat peak temperature may experience necrosis and produce charring. Thischarring reduces the electrical conductivity of the charred tissue,thereby making it more difficult to pass RF current through the targettissue beyond the char and to resistively heat the target tissue beyondthe char. In some embodiments, the peak temperature is between 86° C.and 94° C., between 80° C. and 90° C., 85° C., overlapping rangesthereof, or any temperature value between 80° C. and 95° C.

It may be desirable to heat the volume of target tissue to a minimumtemperature of at least 42° C. When the tissue experiences a temperatureabove 42° C., nerves within the target tissue may be desirably damaged.However, it is believed that denervation is a function of the totalquantum of energy delivered to the target tissue; i.e., both exposuretemperature and exposure time determine the total dose of energydelivered. Accordingly, if the temperature of the target tissue reachesonly about 42° C., then it is believed that the exposure time of thevolume of target tissue to that temperature should be at least about 30minutes and preferably at least 60 minutes in order to deliver the doseof energy believed necessary to denervate the nerves within the targettissue.

It may be desirable to heat the volume of target tissue to a minimumtemperature of at least 50° C. If the temperature of the target tissuereaches about 50° C., then it is believed that the exposure time of thevolume of target tissue to that temperature need only be in the range ofabout 2 minutes to 10 minutes (e.g., about 2-4, 4-6, 6-8, 8-10 minutes)or any duration therebetween to achieve denervation. Shorter timeperiods may also be used.

It may be even more desirable to heat the volume of target tissue to aminimum temperature of at least 60° C. If the temperature of the targettissue reaches about 60° C., then it is believed that the exposure timeof the volume of target tissue to that temperature need only be in therange of about 0.01 minutes to 1.5 minutes to achieve denervation (e.g.,0.1 minutes to 0.25 minutes).

Typically, the period of time that an ION is exposed to therapeutictemperatures is in general related to the length of time in which theelectrodes are activated. In some embodiments, the electrodes, when thepeak temperature is between 80° C. and 95° C., may be activated between10 and 20 minutes, between 10 and 15 minutes, 12 minutes, 15 minutes,less than 10 minutes, greater than 20 minutes, or any duration of timebetween 10 and 20 minutes, to achieve the minimum target tissuetemperature such that the nerve tissue is modulated (e.g., denervated).However, since it has been observed that the total heating zone remainsrelatively hot even after power has been turned off (and the electricfield eliminated), the exposure time can include a period of time inwhich current is not running through the electrodes.

In general, the farther apart the electrodes, the greater the likelihoodthat the ION will be contained within the total heating zone. Therefore,in some embodiments the electrodes are placed at least 5 mm apart or atleast 10 mm apart. However, if the electrodes are spaced too far apart,the electric field takes on an undesirably extreme dumbbell shape.Therefore, in many embodiments, the electrodes are placed apart adistance of between 1 mm and 25 mm, between 5 mm and 15 mm, between 10mm and 15 mm between 3 mm and 10 mm, between 8 mm and 13 mm, between 10mm and 18 mm, between 12 mm and 20 mm between 20 and 25 mm, between 1 mmand 3 mm, or any integer or value between 1 mm and 25 mm.

In some embodiments, it is desirable to heat the target tissue so thatat least about 1 cc of bone tissue experiences the minimum temperature.This volume corresponds to a sphere having a radius of about 0.6 cm.Alternatively stated, it is desirable to heat the target tissue so theminimum temperature is achieved by every portion of the bone within 0.6cm of the point experiencing the peak temperature.

In accordance with several embodiments, it is desirable to heat thetarget tissue so that at least about 3 cc of bone experiences theminimum temperature. This volume corresponds to a sphere having a radiusof about 1 cm (e.g., 0.7 cm, 0.8 cm. 0.9 cm, 1.0 cm, 1.1 cm, 1.2 cm, 1.3cm, 1.4 cm).

Some embodiments provide a steady-state heated zone having a peaktemperature of between 80° C. and 95° C. (e.g., between 86° C. and 94°C., between 80° C. and 90° C., or overlapping ranges thereof), and heatat least 1 cc of bone (e.g., at least 2 cc of bone, at least 3 cc ofbone, at least 4 cc of bone, at least 5 cc of bone) to a temperature ofat least 50° C. (e.g., 60° C.).

In accordance with several embodiments, a method of therapeuticallytreating a vertebral body having a BVN comprises providing an energydevice having an active and a return electrode, inserting the activeelectrode into the vertebral body, inserting the return electrode intothe vertebral body, and applying a sufficiently high frequency voltagedifference between the active and return electrodes to generate acurrent therebetween to produce a total heating zone having a diameterof at least 0.5 cm and a steady state temperature of at least 50° C.

As noted above, a peak temperature below about 100° C. or below about105° C. is desirable in order to prevent charring of the adjacenttissue, steam formation and tissue popping. In some embodiments, this isaccomplished by providing the power supply with a feedback means thatallows the peak temperature within the heating zone to be maintained ata desired target temperature, such as 90° C. In some embodiments, thepeak temperature is in the range of 85° C. to 95° C. In otherembodiments, the peak temperature is between about 70° C. and 90° C.

In some embodiments, between about 24 watts and 30 watts of power isfirst supplied to the device in order to rapidly heat the relativelycool bone, with maximum amperage being obtained within about 10-15seconds. In other embodiments, between about 28 watts and 32 watts ofpower, between about 20 watts and 26 watts of power, between 30 wattsand 40 watts of power, between 15 watts and 24 watts of power,overlapping ranges thereof, or any power level within the ranges, isfirst supplied to the device. In some embodiments, the maximum amperagemay be obtained within 5-10 seconds, within about 15-25 seconds, withinabout 7-12 seconds, within about 13-18 seconds, overlapping rangesthereof, or any duration within the recited ranges. As the bone isfurther heated to the target temperature, the feedback means graduallyreduces the power input to the device to between about 6-10 watts. Insome embodiments, the power input is reduced to between 4-7 watts, about8-12 watts, between 2-6 watts, between about 7-15 watts, or overlappingranges thereto.

Cooling may be employed for any of the neuromodulation devices (e.g.,energy delivery devices) described herein. In several embodiments, acooling balloon or other cooling device or fluid (e.g., heat removalelements, heat sinks, cooling fluid circulating through one or morelumens of the neuromodulation device) is used for cooling the treatmentzone or location or the area surrounding the treatment zone or location.

If the active electrode has no active cooling means, it may becomesubject to conductive heating by the heated tissue, and the resultantincreased temperature in the electrode may adversely affect performanceby charring the adjacent bone tissue. Accordingly, in some embodiments,a cool tip active electrode may be employed. The cooled electrode helpsmaintain the temperature of the electrode at a desired temperature.Cooled tip active electrodes are known in the art. Alternatively, thepower supply may be designed to provide a pulsed energy input. It hasbeen found that pulsing the current favorably allows heat to dissipatefrom the electrode tip, and so the active electrode stays relativelycooler.

In various embodiments, the neuromodulation device comprises anelectrosurgical probe having a shaft with a proximal end, a distal end,and at least one active electrode at or near the distal end. A connectormay be provided at or near the proximal end of the shaft forelectrically coupling the active electrode to a high frequency voltagesource. In some embodiments, a return electrode coupled to the voltagesource is spaced a sufficient distance from the active electrode tosubstantially avoid or minimize current shorting therebetween. Thereturn electrode may be provided integral with the shaft of the probe orit may be separate from the shaft

In some embodiments, the electrosurgical probe or catheter comprises ashaft or a handpiece having a proximal end and a distal end whichsupports one or more electrode terminal(s). The shaft or handpiece mayassume a wide variety of configurations, with the primary purpose beingto mechanically support the active electrode and permit the treatingphysician to manipulate the electrode from a proximal end of the shaft.The shaft may be rigid or flexible, with flexible shafts optionallybeing combined with a generally rigid external tube for mechanicalsupport. Flexible shafts may be combined with pull wires, shape memoryactuators, and other known mechanisms for effecting selective deflectionof the distal end of the shaft to facilitate positioning of theelectrode array. The shaft will usually include a plurality of wires orother conductive elements running axially therethrough to permitconnection of the electrode array to a connector at the proximal end ofthe shaft.

In several embodiments, the shaft is a rigid needle that is introducedthrough a percutaneous penetration in the patient. However, forendoscopic procedures within the spine, the shaft may have a suitablediameter and length to allow the surgeon to reach the target site (e.g.,a disc) by delivering the shaft through the thoracic cavity, the abdomenor the like. Thus, the shaft may have a length in the range of about 5.0to 30.0 cm (e.g., about 5-10, 10-15, 10-20, or 10-30 cm, or overlappingranges thereof), and a diameter in the range of about 0.2 mm to about 10mm (e.g., about 0.2-1, 1-2, 2-4, 2-6, 6-8, or 5-10 mm, or overlappingranges thereof). In any of these embodiments, the shaft may also beintroduced through rigid or flexible endoscopes.

The probe may include one or more active electrode(s) for applyingelectrical energy to tissues within the spine. The probe may include oneor more return electrode(s), or the return electrode may be positionedon the patient's back, as a dispersive pad. In either embodiment,sufficient electrical energy is applied through the probe to the activeelectrode(s) to either necrose the blood supply or nerves within thevertebral body.

The electrosurgical instrument may also be a catheter that is deliveredpercutaneously and/or endoluminally into the patient by insertionthrough a conventional or specialized guide catheter, or the inventionmay include a catheter having an active electrode or electrode arrayintegral with its distal end. The catheter shaft may be rigid orflexible, with flexible shafts optionally being combined with agenerally rigid external tube for mechanical support. Flexible shaftsmay be combined with pull wires, shape memory actuators, and other knownmechanisms for effecting selective deflection of the distal end of theshaft to facilitate positioning of the electrode or electrode array. Thecatheter shaft may include a plurality of wires or other conductiveelements running axially therethrough to permit connection of theelectrode or electrode array and the return electrode to a connector atthe proximal end of the catheter shaft. The catheter shaft may include aguide wire for guiding the catheter to the target site, or the cathetermay comprise a steerable guide catheter. The catheter may also include asubstantially rigid distal end portion to increase the torque control ofthe distal end portion as the catheter is advanced further into thepatient's body. Specific deployment means will be described in detail inconnection with the figures hereinafter.

In some embodiments, the electrically conductive wires may run freelyinside the catheter bore in an unconstrained made, or within multiplelumens within the catheter bore.

The tip region of the instrument may comprise many independent electrodeterminals designed to deliver electrical energy in the vicinity of thetip. The selective application of electrical energy is achieved byconnecting each individual electrode terminal and the return electrodeto a power source having independently controlled or current limitedchannels. The return electrode(s) may comprise a single tubular memberof conductive material proximal to the electrode array. Alternatively,the instrument may comprise an array of return electrodes at the distaltip of the instrument (together with the active electrodes) to maintainthe electric current at the tip. The application of high frequencyvoltage between the return electrode(s) and the electrode array resultsin the generation of high electric field intensities at the distal tipsof the electrode terminals with conduction of high frequency currentfrom each individual electrode terminal to the return electrode. Thecurrent flow from each individual electrode terminal to the returnelectrode(s) is controlled by either active or passive means, or acombination thereof, to deliver electrical energy to the surroundingconductive fluid while minimizing or preventing energy delivery tosurrounding (non-target) tissue, such as the spinal cord.

Temperature probes associated with the apparatus may be disposed on orwithin the electrode carrier; between the electrodes (may be preferredin bipolar embodiments); or within the electrodes (may be preferred formonopolar embodiments). In some embodiments wherein the electrodes areplaced on either side of the ION, a temperature probe is disposedbetween the electrodes or in the electrodes. In alternate embodiments,the deployable portion of the temperature probe comprises a memorymetal.

The electrode terminal(s) may be supported within or by an inorganicinsulating support positioned near the distal end of the instrumentshaft. The return electrode may be located on the instrument shaft, onanother instrument or on the external surface of the patient (i.e., adispersive pad). In some embodiments, the close proximity of the dualneedle design to the intraosseous nerve makes a bipolar design morepreferable because this minimizes the current flow through non-targettissue and surrounding nerves. Accordingly, the return electrode ispreferably either integrated with the instrument body, or anotherinstrument located in close proximity thereto. The proximal end of theinstrument(s) may include the appropriate electrical connections forcoupling the return electrode(s) and the electrode terminal(s) to a highfrequency power supply, such as an electrosurgical generator.

In some embodiments, the active electrode(s) have an active portion orsurface with surface geometries shaped to promote the electric fieldintensity and associated current density along the leading edges of theelectrodes. Suitable surface geometries may be obtained by creatingelectrode shapes that include preferential sharp edges, or by creatingasperities or other surface roughness on the active surface(s) of theelectrodes. Electrode shapes can include the use of formed wire (e.g.,by drawing round wire through a shaping die) to form electrodes with avariety of cross-sectional shapes, such as square, rectangular, L or Vshaped, or the like. The electrodes may be tip electrodes, ringelectrodes, plate electrodes, cylindrical electrodes, frustoconicalelectrodes, or any other shape electrodes. Electrode edges may also becreated by removing a portion of the elongate metal electrode to reshapethe cross-section. For example, material can be ground along the lengthof a round or hollow wire electrode to form D or C shaped wires,respectively, with edges facing in• the cutting direction.Alternatively, material can be removed at closely spaced intervals alongthe electrode length to form transverse grooves, slots, threads or thelike along the electrodes. In other embodiments, the probe can besectored so that a given circumference comprises an electrode-region andan inactive region. In some embodiments, the inactive region is masked.

The return electrode is typically spaced proximally from the activeelectrode(s) a suitable. In most of the embodiments described herein,the distal edge of the exposed surface of the return electrode is spacedabout 1 to 25 mm (or any distance therebetween) from the proximal edgeof the exposed surface of. the active electrode(s), in dual needleinsertions. Of course, this distance may vary with different voltageranges, the electrode geometry and depend on the proximity of tissuestructures to active and return electrodes. In several embodiments, thereturn electrode has an exposed length in the range of about 1 to 20 mm,about 2 to 6 mm, about 3 to 5 mm, about 1 to 8 mm, about 4 to 12 mm,about 6 to 16 mm, about 10 to 20 mm, 4 mm, 5 mm, 10 mm, or any lengthbetween 1 and 20 mm. The application of a high frequency voltage betweenthe return electrode(s) and the electrode terminal(s) for appropriatetime intervals effects modifying the target tissue. In severalembodiments, the electrodes have an outer diameter of between 1 and 2 mm(e.g., between 1 and 1.5 mm, between 1.2 and 1.8 mm, between 1.5 and 1.7mm, between 1.6 and 2 mm, 1.65 mm, or any outer diameter between therecited ranges). In several embodiments, the electrodes have an innerdiameter of between 0.5 and 1.5 mm (e.g., between 0.5 and 0.8 mm,between 0.75 and 0.9 mm, between 0.8 and 1 mm, between 1 mm and 1.5 mm,0.85 mm, or any inner diameter between the recited ranges).

Embodiments may use a single active electrode terminal or an array ofelectrode terminals spaced around the distal surface of a catheter orprobe. In the latter embodiment, the electrode array usually includes aplurality of independently current limited and/or power-controlledelectrode terminals to apply electrical energy selectively to the targettissue while limiting the unwanted application of electrical energy tothe surrounding tissue and environment resulting from power dissipationinto surrounding electrically conductive fluids, such as blood, normalsaline, and the like. The electrode terminals may be independentlycurrent-limited by isolating the terminals from each other andconnecting each terminal to a separate power source that is isolatedfrom the other electrode terminals. Alternatively, the electrodeterminals may be connected to each other at either the proximal ordistal ends of the catheter to form a single wire that couples to apower source.

In one configuration, each individual electrode terminal in theelectrode array is electrically insulated from all other electrodeterminals in the array within said instrument and is connected to apower source which is isolated from each of the other. electrodeterminals in the array or to circuitry which limits or interruptscurrent flow to the electrode terminal when low resistivity material(e.g., blood) causes a lower impedance path between the return electrodeand the individual electrode terminal. The isolated power sources foreach individual electrode terminal may be separate power supply circuitshaving internal impedance characteristics which limit power to theassociated electrode terminal when a low impedance return path isencountered. By way of example, the isolated power source may be a userselectable constant current source. In one embodiment, lower impedancepaths may automatically result in lower resistive heating levels sincethe heating is proportional to the square of the operating current timesthe impedance. Alternatively, a single power source may be connected toeach of the electrode terminals through independently actuatableswitches, or by independent current limiting elements, such asinductors, capacitors, resistors and/or combinations thereof. Thecurrent limiting elements may be provided in the instrument, connectors,cable, controller, or along the conductive path from the controller tothe distal tip of the instrument. Alternatively, the resistance and/orcapacitance may occur on the surface of the active electrode terminal(s)due to oxide layers which form selected electrode terminals (e.g.,titanium or a resistive coating on the surface of me till, such asplatinum).

In one embodiment of the invention, the active electrode comprises anelectrode array having a plurality of electrically isolated electrodeterminals disposed over a contact surface, which may be a planar ornon-planar surface and which may be located at the distal tip or over alateral surface of the shaft, or over both the tip and lateralsurface(s). The electrode array may include at least two or moreelectrode terminals and may further comprise a temperature sensor. Inone embodiment, each electrode terminal may be connected to the proximalconnector by an electrically isolated conductor disposed within theshaft. The conductors permit independent electrical coupling of theelectrode terminals to a high frequency power supply and control systemwith optional temperature monitor for operation of the probe. Thecontrol system may advantageously incorporate active and/or passivecurrent limiting structures, which are designed to limit current flowwhen the associated electrode terminal is in contact with a lowresistance return path back to the return electrode.

The use of such electrode arrays in electrosurgical procedures may beparticularly advantageous as it has been found to limit the depth oftissue necrosis without substantially reducing power delivery. Thevoltage applied to each electrode terminal causes electrical energy tobe imparted to any body structure which is contacted by, or comes intoclose proximity with, the electrode terminal, where a current flowthrough all low electrical impedance paths is preferably but notnecessarily limited. Since some of the needles are hollow, a conductivefluid could be added through the needle and into the bone structure forthe purposes of lowering the electrical impedance and fill the spaces inthe cancellous bone to make them better conductors to the needle.

It should be clearly understood that the invention is not limited toelectrically isolated electrode terminals, or even to a plurality ofelectrode terminals. For example, the array of active electrodeterminals may be connected to a single lead that extends through thecatheter shaft to a power source of high frequency current.Alternatively, the instrument may incorporate a single electrode thatextends directly through the catheter shaft or is connected to a singlelead that extends to the power source. The active electrode(s) may haveball shapes, twizzle shapes, spring shapes, twisted metal shapes, coneshapes, annular or solid tube shapes or the like. Alternatively, theelectrode(s) may comprise a plurality of filaments, rigid or flexiblebrush electrode(s), side-effect brush electrode(s) on a lateral surfaceof the shaft, coiled electrode(s) or the like.

The voltage difference applied between the return electrode(s) and theelectrode terminal(s) can be at high or radio frequency (e.g., betweenabout 50 kHz and 20 MHz, between about 100 kHz and 2.5 MHz, betweenabout 400 kHz and 1000 kHz, less than 600 kHz, between about 400 kHz and600 kHz, overlapping ranges thereof, 500 kHz, or any frequency withinthe recited ranges. The RMS (root mean square) voltage applied may be inthe range from about 5 volts to 1000 volts, in the range from about 10volts to 200 volts, between about 20 to 100 volts, between about 40 to60 volts, depending on the electrode terminal size, the operatingfrequency and the operation mode of the particular procedure. Lowerpeak-to-peak voltages may be used for tissue coagulation, thermalheating of tissue, or collagen contraction and may be in the range from50 to 1500, from 100 to 1000, from 120 to 400 volts, from 100 to 250volts, from 200 to 600 volts, from 150 to 350 volts peak-to-peak,overlapping ranges thereof, or any voltage within the recited ranges. Asdiscussed above, the voltage may be delivered continuously with asufficiently high frequency (e.g., on the order of 50 kHz to 20 MHz) (ascompared with e.g., lasers claiming small depths of necrosis, which aregenerally pulsed about 10 to 20 Hz). In addition, the sine wave dutycycle (i.e., cumulative time in anyone-second interval that energy isapplied) may be on the order of about 100%, as compared with pulsedlasers which typically have a duty cycle of about 0.0001%. In variousembodiments, the current ranges from 50 to 300 mA (e.g., from 50 to 150mA, from 100 to 200 mA, from 150 to 300 mA, overlapping ranges thereof,or any current level within the recited ranges).

A power source may deliver a high frequency current selectable togenerate average power levels ranging from several milliwatts to tens ofwatts per electrode, depending on the volume of target tissue beingheated, and/or the maximum allowed temperature selected for theinstrument, tip. The power source allows the user to select the powerlevel according to the specific requirements of a particular procedure.

The power source may be current limited or otherwise controlled so thatundesired heating of the target tissue or surrounding (non-target)tissue does not occur. In one of the presently preferred embodiments,current limiting inductors are placed in series with each independentelectrode terminal, where the inductance of the inductor is in the rangeof 10 uH to 50,000 uH, depending on the electrical properties of thetarget tissue, the desired tissue heating rate and the operatingfrequency. Alternatively, capacitor-inductor (LC) circuit structures maybe employed, as described previously in U.S. Pat. No. 5,697,909.Additionally, current limiting resistors may be selected. In severalembodiments, microprocessors are employed to monitor the measuredcurrent and control the output to limit the current.

The area of the tissue treatment surface can vary widely, and the tissuetreatment surface can assume a variety of geometries, with particularareas and geometries being selected for specific applications. Thegeometries can be planar, concave, convex, hemispherical, conical,linear “in-line” array or virtually any other regular or irregularshape. Most commonly, the active electrode(s) or electrode terminal(s)can be formed at the distal tip of the electrosurgical instrument shaft,frequently being planar, disk-shaped, ring-shaped, or hemisphericalsurfaces for use in reshaping procedures or being linear arrays for usein cutting. Alternatively or additionally, the active electrode(s) maybe formed on lateral surfaces of the electrosurgical instrument shaft(e.g., in the manner of a spatula), facilitating access to certain bodystructures in endoscopic procedures.

The devices may be suitably used for insertion into any hard tissue inthe human body. In some embodiments, the hard tissue is bone. In otherembodiments, the hard tissue is cartilage. In some embodiments when boneis selected as the tissue of choice, the bone is a vertebral body. Inseveral embodiments, devices are adapted to puncture the hard corticalshell of the bone and penetrate at least a portion of the underlyingcancellous bone. In some embodiments, the probe advances into the boneto a distance of at least ⅓ of the cross-section of the bone defined bythe advance of the probe. Some method embodiments are practiced invertebral bodies substantially free of tumors. In others, methodembodiments are practiced in vertebral bodies having tumors.

In some embodiments using two separate probes, the device enters thehard tissue (e.g., bone such as the vertebral body) through two accesspoints. In some embodiments, the pair of separate probes is adapted todenervate the BVN and enter through separate pedicles transpedicularly.In other embodiments, the pair of separate probes each enters thevertebral body extrapedicularly. In other embodiments, a first of thepair of separate probes enters the vertebral body extrapedicularly andthe second enters the vertebral body transpedicularly. In embodimentsusing a single device, the device enters via a single pedicle. In suchembodiments, both the active and return electrodes may be disposed on asingle probe, which may be placed transpedicularly via either the leftpedicle or the right pedicle, such that one electrode crosses themidline and the second electrode remains on the same side of the midlineas the pedicle entered. Thus, energy transmitted between the twoelectrodes effectively targets the BVN, which is disposed between thetwo electrodes. In some embodiments, this may be accomplished byutilizing a curved probe, such that the distal electrode may be placedat or near the tip of the probe and the proximal electrode may be placedat or near the starting point of the curve. Therefore, upon deploymentof the probe in the vertebral body, the two electrodes of the singleprobe end up on either side of the midline at approximately the sameanterior-posterior position. In other embodiments, a single probe with afixed segment and a pivotable segment, in which at least one active andone return electrode are located on the single probe. Either or bothelectrodes may be located on the fixed segment or the pivotable segment.A single probe, with two electrodes placed on the probe, may also beused via extrapedicular entrance to the vertebral body.

Now referring to FIG. 45, in some embodiments, the target region of theBVN is located within the cancellous portion of the bone (i.e., to theinterior of the outer cortical bone region) and proximal to the junctionJ of the BVN having a plurality of branches. In accordance with severalembodiments, treatment in this region is advantageous because only asingle portion of the BVN or a small number of initial branches need beeffectively treated to denervate the entire system. In some embodiments,treatment of the BVN in locations more downstream than the junction J ortreatment location T may require the denervation of each branch.

EXAMPLES

The following Examples illustrate some embodiments of the invention andare not intended in any way to limit the scope of the disclosure.Moreover, the methods and procedures described in the followingexamples, and in the above disclosure, need not be performed in thesequence presented.

Example I

This example describes an embodiment of a method of use of one of thedual probe embodiments.

First, after induction of an appropriate amount of a local anesthesia,the human patient is placed in a prone position on the table. The C-armof an X-ray apparatus is positioned so that the X-rays are perpendicularto the axis of the spine. This positioning provides a lateral view ofthe vertebral body, thereby allowing the surgeon to view the access ofthe apparatus into the vertebral body.

Next, a cannulated stylet comprising an inner stylet and an outercannula are inserted into the skin above each of the respective pediclesso that the distal tip of each stylet is in close proximity to therespective pedicle.

Next, the probe is advanced interiorly into the body so that the stylettips bores through the skin, into and through the pedicle, and then intothe vertebral body. The stylet is advanced until the tips reach theanterior-posterior midline of the vertebral body.

Next, the stylet is withdrawn and probe is inserted into the cannula andadvanced until the first and second electrodes thereof each reach themidline of the vertebral body. The location of the two probes is shownfrom various perspectives in FIGS. 46A-46D. As shown, the probes can beinserted using a transpedicular access approach.

Next, the power supply is activated to provide a voltage between thefirst and second electrodes. The amount of voltage across the electrodesis sufficient to produce an electric current between the first andsecond electrodes. This current provides resistive heating of the tissuedisposed between the electrodes in an amount sufficient to raise thetemperature of the local portion of the BVN to at least 45° C., therebydenervating the BVN.

Example II

This example describes the efficacy of heating a large zone of avertebral body with an embodiment of a bipolar energy device. Inaccordance with one embodiment, the testing procedure was performed asfollows:

A pair of probes was inserted into a vertebral body of an ovine animalmodel so that the tips of the electrodes were located substantially atthe midline and separated by about 4 mm. Each electrode had acylindrical shape, a length of about 20 mm, and an outer diameter ofabout 1.65 mm (16 gauge) to produce a surface area of about 100 mm².

Next, and now referring to FIGS. 47A and 47B, thermocouples 0-14 wereplaced within the vertebral body at the 15 locations. Thermocouples 0-4were placed halfway between the electrode tips and were separated by adistance of 2 mm. Thermocouples 5-9 were placed about at the midpointbetween the probe tips, and were vertically separated by a distance of 2mm Thermocouples 10-14 were placed along the distal portion of the probeand were separated by a distance of 5 mm.

Next; about 57 volts of energy was applied across the electrodes, andthe temperature rise in the tissue was recorded at the thermocouplesites. These temperatures are provided in FIGS. 48A-48C. In general, thetemperature at each site rose somewhat steadily from about 22° C. to itspeak temperature in about 200-300 seconds, whereupon feedback controlsmaintained the peak temperatures.

FIGS. 49A and 49B provide the peak-temperatures recorded by eachthermocouple. Analysis of the results in FIGS. 49A and 49B reveals thatpeak temperatures of between about 80° C. and 95° C. were able to besustained over substantial distances. In particular, a temperature of79.4 degrees was reached about 10 mm along the electrode (T11);temperatures of between 76.7 and 80.3° C. were reached at a depth ofabout 4 mm within the tissue (T5 and T9); and a temperature of 76.8° C.was reached about 10 mm along the electrode (T3).

The positive results provided by this example have great significance tothe problem of therapeutically heating IONs, and the BVN in particular.In particular, the results of thermocouples T5-9 indicates that if anION were located along the z-axis within 2 mm of the presumed center ofthe IRZ, then the ION could be sufficiently treated to at least 80° C.Similarly, the results of thermocouples T 0-4 indicate that as much as a16 mm length of ION could be sufficiently treated to at least 80° C.Lastly, the results of thermocouples T 10-14 indicate that the ION couldbe off-center laterally in the IRZ by as much as 2 mm and at least about10 mm of its length could be sufficiently treated to at least 80° C.

Example III

This embodiment describes an example of a method of use of anarticulated probe. In accordance with one embodiment, the method isperformed as follows:

The initial steps described above in Example I can be carried out sothat the articulated probe is poised on the patient's skin and held inplace by a ratchet type gun. See FIG. 50A.

Next, the distal end of the articulated probe is inserted into the skinabove a pedicle so that the distal end of the fixed probe is in closeproximity to the pedicle.

Now referring to FIG. 50B, the probe is advanced interiorly into thebody so that the distal tip bores through the skin, into and through thepedicle, and then into the vertebral body. The distal tip is advanceduntil it reaches about 30% beyond the anterior posterior midline of thevertebral body.

Now referring to FIG. 50C, the distal end of the pusher rod is insertedinto the bore of the fixed probe and advanced until the angled portionof the pusher rod contacts the angled portion of the pivotable probe,thereby nudging the pivotable probe out of the recess. The pivotableprobe is now in a partially deployed mode.

Now referring to FIG. 50D, the apparatus is slightly withdrawn from thebody. As this occurs, the bone disposed between the pivotable and fixedprobes prevents the pivotable probe from withdrawing along with thefixed probe, but rather forces open the pivoting means, thereby bringingthe axis of the pivotable probe to a position substantially normal tothe axis of the fixed probe. The pivotable probe is now in extendedmode.

Next, the power supply is activated to provide a voltage between thefirst and second electrodes. The amount of voltage across the electrodesis sufficient to produce an electric current between the first andsecond electrodes. This current provides resistive heating of the tissuedisposed between the electrodes in an amount sufficient to raise thetemperature of the local portion of the BVN to at least 45° C., therebydenervating the BVN. In some embodiments, the temperature of the localportion of the BVN may be raised to between 40° C. and 100° C., between40° C. and 60° C., between about 45° C. and 55° C., between 50° C. and90° C., between 60° C. and 80° C., or in overlapping ranges thereof.

Next, the fixed probe is pushed forward to bring the pivotable probeback into the recess. Now referring to FIG. 50E, the probe is removedfrom the body.

Example IV

Now referring to FIG. 51, there is provided a dual articulated needleembodiment wherein the articulated needles are each advanced down thepedicles of the vertebral body, and each of the pivotable probes aredeployed at an angle of less than 90 degrees, so that the electrodesthereon align themselves in an essentially parallel relationship.Because the electric field produced by this embodiment is relativelyeven between the electrodes, the resulting total heating zone is alsodesirably homogeneous. Because the electrodes deploy in the centralposterior portion of the vertebral body, the BVN is desirably denervatednear its trunk (e.g., at or posterior to a junction or terminus of theBVN).

Example V

A pilot human clinical study was performed to determine efficacy of aminimally invasive technique involving ablation of the basivertebralnerve in providing relief to patients with chronic lower back pain.

In the present study, a radiofrequency device was used to ablate thenerves within the vertebral bone that transmit pain signals. The studyinvolved treatment of 16 human patients with chronic (greater than 6months) isolated lower back pain who were unresponsive to at least 3months of nonsurgical conservative care. The patients treated andobserved in the study were an average of 47.6 years old and hadundergone an average of 32.4 months of conservative treatment. Thepatients all had Oswestry Disability Index (ODI) scores greater than 30and either pathologic changes or positive provocative discography at thetargeted degenerated disc level.

In accordance with several embodiments, the intraosseous course of thebasivertebral foramen for the targeted vertebral bodies was visualizedand mapped using MRI imaging (e.g., anteroposterior and lateral stillimages). CT or other imaging techniques can also be used. In the study,treatment was performed using intraoperative fluoroscopy and atranspedicular approach; however, other visualization and approachtechniques can be used. The treatment device used during the study was abipolar radiofrequency probe with a curved obturator. In the study, thebipolar RF probe was inserted through a bone biopsy needle and guided tothe target treatment location under fluoroscopy. The bipolar RF probewas then used to ablate the basivertebral nerve in a controlled manner.The RF energy delivered in the study had a frequency of 500 kHz, thetemperature at the electrodes was 85° C., and the duration of treatmentvaried between 5 and 15 minutes. In accordance with several embodiments,the RF energy delivered may be between 400 and 600 kHz (e.g., 450 kHz,500 kHz, 550 kHz), the temperature at the electrodes may be between 80°C. and 100° C. (e.g., 85° C., 90° C., 95° C.), and the duration oftreatment may be between 4 and 20 minutes (e.g., 6 minutes, 8 minutes,10 minutes, 12 minutes, 15 minutes).

In accordance with several embodiments, the treatment was limited to theL3, L4, L5 and S1 vertebrae. Two-level and three-level intraosseousablation treatments were performed on various patients. The multiplelevels treated during the study were at adjacent levels. Twelve patientswere treated at the L4 and L5 levels, two patients were treated at L3through L5 levels, and two patients were treated at the L5 and S1levels.

Radiographs found no fractures during the follow-up period, and noremodeling of bone was observed. Thirteen of the sixteen patientsreported “profound and immediate relief.” The treatment procedureresulted in improved ODI scores and Visual Analogue Pain Scale (VAS)values, which were sustained at one year. ODI scores were significantlyimproved at six weeks, three months, six months, and twelve months. Themean decrease in ODI scores at 1 year was 31 points. VAS valuesdecreased from a preoperative average of 61.1 to an average of 45.6 atthe 1-year follow-up. No device-related serious adverse events werereported. Accordingly, in one embodiment, basivertebral nerve ablationis a safe, simple procedure that is applicable during the early stagesof treatment for patients with disabling back pain.

Conditional language, for example, among others, “can,” “could,”“might,” or “may,” unless specifically stated otherwise, or otherwiseunderstood within the context as used, is generally intended to conveythat certain embodiments include, while other embodiments do notinclude, certain features, elements and/or steps.

Although certain embodiments and examples have been described herein,aspects of the methods and devices shown and described in the presentdisclosure may be differently combined and/or modified to form stillfurther embodiments. Additionally, the methods described herein may bepracticed using any device suitable for performing the recited steps.Some embodiments have been described in connection with the accompanyingdrawings. However, it should be understood that the figures are notdrawn to scale. Distances, angles, etc. are merely illustrative and donot necessarily bear an exact relationship to actual dimensions andlayout of the devices illustrated. Components can be added, removed,and/or rearranged. Further, the disclosure (including the figures)herein of any particular feature, aspect, method, property,characteristic, quality, attribute, element, or the like in connectionwith various embodiments can be used in all other embodiments set forthherein.

For purposes of this disclosure, certain aspects, advantages, and novelfeatures of the inventions are described herein. Embodiments embodied orcarried out in a manner may achieve one advantage or group of advantagesas taught herein without necessarily achieving other advantages. Theheadings used herein are merely provided to enhance readability and arenot intended to limit the scope of the embodiments disclosed in aparticular section to the features or elements disclosed in thatsection. The features or elements from one embodiment of the disclosurecan be employed by other embodiments of the disclosure. For example,features described in one figure may be used in conjunction withembodiments illustrated in other figures.

Although the description above contains many details, these should notbe construed as limiting the scope of the invention(s) but as merelyproviding illustrations of some of the embodiments of this invention.Therefore, the scope of the invention(s) described herein fullyencompasses other contemplated embodiments, as well as theirequivalents. The scope of the invention should be viewed in light of theappended claims. References herein to an element in the singular is notintended to mean “one and only one” unless explicitly so stated, butrather “one or more.”

1. (canceled)
 2. A method of treating back pain, the method comprising:inserting a cryotherapy device within a vertebral body, wherein thevertebral body is a vertebral body of a lumbar vertebra or a sacralvertebra; applying cooling at a target treatment location within thevertebral body using the cryotherapy device, wherein the targettreatment location comprises a portion of a basivertebral nerve, whereinthe cooling is configured to provide localized treatment sufficient todisrupt transmission of pain signals along the portion of thebasivertebral nerve, wherein the cooling comprises use of liquid nitrousoxide, wherein the cooling is configured to cool tissue of the targettreatment location within the vertebral body to a temperature of between−20 and −40 degrees Celsius, and wherein the cooling is delivered in oneor more freeze cycles; and performing diagnostic stimulation of theportion of the basivertebral nerve within the vertebral body.
 3. Themethod of claim 2: wherein the vertebral body is a vertebral body of anL5 vertebra or an S1 vertebra, wherein the cooling is sufficient topermanently disrupt transmission of pain signals along the portion ofthe basivertebral nerve, wherein inserting the cryotherapy device withinthe vertebral body comprises inserting the cryotherapy device through anintroducer previously inserted within the vertebral body, wherein themethod further comprises performing imaging prior to inserting thecryotherapy device to identify the target treatment location within thevertebral body, and wherein the method further comprises removing thecryotherapy device from the vertebral body.
 4. The method of claim 2,wherein the cooling is sufficient to permanently disrupt transmission ofpain signals along the portion of the basivertebral nerve.
 5. The methodof claim 2, wherein the cooling is sufficient to ablate thebasivertebral nerve.
 6. The method of claim 2, wherein the temperatureis maintained for 5 to 20 minutes.
 7. A method of treating back pain,the method comprising: inserting a cryotherapy device within a vertebralbody, applying cooling at a target treatment location within thevertebral body using the cryotherapy device, wherein the targettreatment location comprises a portion of a basivertebral nerve, whereinthe cooling is configured to provide localized treatment sufficient todisrupt transmission of pain signals along the portion of thebasivertebral nerve, wherein the cooling is configured to cool tissue ofthe target treatment location within the vertebral body to a temperatureof between −20 and −80 degrees Celsius, and wherein the cooling isdelivered in one or more cycles; and performing diagnostic stimulationof the portion of the basivertebral nerve within the vertebral body. 8.The method of claim 7: wherein the vertebral body is a vertebral body ofan L5 vertebra or an S1 vertebra, wherein the cooling is sufficient topermanently disrupt transmission of pain signals along the portion ofthe basivertebral nerve, wherein inserting the cryotherapy device withinthe vertebral body comprises inserting the cryotherapy device through anintroducer previously inserted within the vertebral body, and whereinthe method further comprises removing the cryotherapy device from thevertebral body.
 9. The method of claim 7, wherein the cooling comprisescirculating fluid within one or more lumens of the cryotherapy device.10. The method of claim 7, wherein the temperature is between −20 and−50 degrees Celsius.
 11. The method of claim 7, wherein the temperatureis between −20 and −40 degrees Celsius.
 12. The method of claim 7,further comprising performing imaging prior to inserting the cryotherapydevice to identify the target treatment location within the vertebralbody.
 13. The method of claim 7, wherein the cooling comprises use ofliquid nitrous oxide.
 14. A method of treating back pain, the methodcomprising: inserting a cryotherapy device to a location of a vertebralbody, applying cooling to a portion of a basivertebral nerve associatedwith the vertebral body using the cryotherapy device, wherein thecooling is configured to provide localized treatment sufficient todisrupt transmission of pain signals along the portion of thebasivertebral nerve, wherein the cooling is configured to cool theportion of the basivertebral nerve to a temperature of between −20 and−80 degrees Celsius, and wherein the cooling is delivered in one or morecycles.
 15. The method of claim 14: wherein the vertebral body is avertebral body of an L5 vertebra or an S1 vertebra, wherein the coolingis sufficient to permanently disrupt transmission of pain signals alongthe portion of the basivertebral nerve, wherein the temperature isbetween −20 and −40 degrees Celsius, and wherein inserting thecryotherapy device to a location of the vertebral body comprisesinserting the cryotherapy device within the vertebral body.
 16. Themethod of claim 14, further comprising performing diagnostic stimulationof the portion of the basivertebral nerve.
 17. The method of claim 14,wherein the cooling comprises circulating fluid within one or morelumens of the cryotherapy device.
 18. The method of claim 14, whereinthe temperature is between −20 and −50 degrees Celsius.
 19. The methodof claim 14, wherein the temperature is between −20 and −40 degreesCelsius.
 20. The method of claim 14, further comprising performingimaging prior to inserting the cryotherapy device to identify the targettreatment location within the vertebral body.
 21. The method of claim14, wherein the cooling comprises use of liquid nitrous oxide.